The MC is an ordinary village boy who was given OP healing powers that reset the target to it's natural state. Unfortunately, using this power to heal causes him to feel all the pain the target went through, so the MC refuses to use his power.
He is then locked up by the other heroes, drugged and conditioned to heal in exchange for more drugs. He eventually develops resistance to the drugs, regains his sanity and manages to obtain an OP power allowing to "heal" the world and reset time to before he became a hero.
Ths time round he will use his OP healing powers to obtain a harem and revenge on the other heroes from the previous timeline.
Serialized in Young Ace UP. RAW: https://web-ace.jp/youngaceup/contents/1000049/