A bacta tank can't regrow severed limbs but they can handle the majority of flesh based injuries.
Bacta was a thick, gelatinous substance with near-miraculous healing properties. It helped the body regrow tissue, including nerves, skin, and muscles.
Bacta was often thought of as a "miracle fluid" and seemed to be effective against almost every type of injury and ailment across an incredible cross-section of species throughout the galaxy. It was considered the best medicine available anywhere, replacing the previously used kolto.
Bacta Tanks are person-sized pods filled with a gelatinous liquid called “bacta” that possesses incredible rapid healing abilities. Bacta is capable of regenerating the human body by healing injuries and replacing scar tissue. It also provides pain relief.
Bacta tanks were large vessels filled with a liquid healing agent and used to treat seriously injured patients. To promote healing, patients were completely submerged and used breathing masks while recuperating. Clone troopers were treated in bacta at facilities such as the Kaliida Shoals Medical Center.
Bactade was an edible form of bacta that was introduced some time prior to 9 ABY. A muddy liquid that was dispensed in bottles, bactade possessed good healing qualities, however it had a terrible, chalky taste.
Simply put, Vader's wounds were far too serious for bacta to heal entirely. If bacta were able to do that, then neither Anakin nor Luke would have prosthetic arms.
Darth Vader's Bacta Tank Recovery Period
It is depicted that the Bacta Tank can heal a wide range of cuts, diseases, and even broken bones, but the time varies every time.
Palpatine chose to keep his face as a symbol of the Jedi's treachery and as a way to appear weak to his enemies. The Sith Lord's rise to power based itself on appearing weaker than he actually was, and he continued that until his death.
Boba Fett ended up inside Sarlacc's stomach [1]. While being digested alive and close to being breathless, Boba Fett was exposed to the digestive enzymes of the giant intergalactic monster. Due to this, Boba Fett's skin was burned and ended up scarred.
Audiences got to see how the man got his burns in Star Wars: Episode III - Revenge of the Sith. Those burns were incredibly severe and covered most of Anakin Skywalker's face. Judging by his face at the end of Return of the Jedi, the burns have healed quite a bit in the 22 years since his fight with Obi-Wan Kenobi.
A bacta tank and a supply of bacta were expensive, the tank alone typically costing 100,000 credits from 32 BBY to 8 ABY, and so such medical equipment was usually found only in hospitals, on board capital ships, and within major military bases.
It's possible that he initially used the Bacta Pod for his skin condition, but then developed an addiction to it over time. This could have formed a part of the story with the Mandalorian battling his addiction along with everything else he and Fennec Shand must face together, but this doesn't appear to be the case.
Luke Skywalker used a bacta tank after his encounter with the ice monster in the Hoth in The Empire Strikes Back, and Darth Vader also used a bacta when studying the dark side. With the bacta tank, the wounds, injuries, and pain that Boba Fett feels healed.
While technologies like prosthetics have advanced, doctors are still unable to induce human limb regeneration.
Unlike some of our invertebrate and vertebrate cousins with the capacity to regenerate limbs after traumatic loss, humans do not have the ability to regrow arms or legs lost to injury or disease.
Even though Kylo Ren uses a red lightsaber, harnesses the dark side of the Force, and wears a cape, he is not a Sith. Because of that, he can never hold the title of Darth. Instead, he was just a chaotic mess of the dark side (until he eventually found his way back to the light).
The individual would pull their dark powers into themselves and adopt a mask of insignificance. This projected illusion would enable a Sith to hide in plain sight whenever they would go out in public.
The Rise of Skywalker novelization
In the book, it is revealed that Palpatine had discovered Plagueis' "secret to immortality", using this knowledge to resurrect himself after his death in Return of the Jedi.
Because Palpatine didn't want him healed. He wanted Vader injured and suffering to give him pain to anchor him to the Dark Side but most importantly to 'make sure' Vader would never be able to be physically powerful enough to overthrow him.
History. Bacta tanks already existed during the Clone Wars, when the Galactic Republic used them to treat its injured soldiers. A bacta tank was located in Darth Vader's castle on Mustafar, where the Dark Lord would relax and meditate outside of his life support armor with a modicum of comfort.
Once your broken bone heals fully, it should be just as strong as the rest of your bones, so you won't be more or less likely to break it than another bone.
Purpose. Darth Vader's meditation chamber was a life support pod that allowed the Sith Lord to survive for extended periods without the helmet and mask of his suit. The injuries Vader sustained during his duel against Obi-Wan Kenobi on Mustafar normally made this impossible.
After all, SOMEBODY had to train Luke in order to defeat Darth Vader and the rest of the Empire. So how many Jedi died during the attack? Almost 10,000—meaning that only 0.2% of Jedi survived.
This is the man who brought everything full circle for Vader and, even though the dark lord of the Sith has to fear or respect no one, he clearly offers some level of respect to the feared bounty hunter they call Boba Fett.