Is one permitted to undergo hypnosis to try to reveal memories of a past life? I saw in a different answer on this site that it’s permissible to undergo hypnosis to correct a bad midda. Are both the same thing but with different consequences?

ב"ה Shalom The use of hypnosis for medical or other therapeutic purposes, it is not considered a form of idol worship or sorcery and therefore it is permitted. However, since there is a measure of self-ridicule because of the mental state a person is brought to, it should not be used for other purposes. (Binyan Tzion 67, Igrot Moshe Yoreh De'ah 3: 44, Medical halachic Encyclopedia, under the entry of "shoteh.") As far as delving into a past life, after has spoken to someone in the clinical field, I was told there is no scientific basis to a past life and it is purely anecdotal, therefore I don't know what hypnosis can help from that point of view. However from a spiritual point of view I suggest staying away from realms which are beyond our grasp, understanding and responsibility. We are responsible for that which is revealed and known to us and not for that which is concealed. All the best