If you're an average or below average guy, the moment you become self-conscious about your physical appearance and uncomfortable in your own skin, you're screwed. Your mental health will be compromised and you're probably never going to experience life in the same way.

You might think "Blackpill is at fault for this" but you'd be wrong. Becoming blackpilled is a symptom, not the cause. IRL stuff like being bullied, cast out, rejected too much, being invisible to girls or simply comparing yourself to someone more attractive are all things that can trigger this kind of thoughts. Even if you're bluepilled you might still have this thoughts, because even bluepilled people have an instinctive grasp of beauty standards.

Moreover dating will become a lot harder because your confidence, self esteem and social skills will worsen. You'll also probably start craving validation in a needy way that will turn off most girls.

Personally I think that no amount of therapy or healthy hobbies can revert this. IMO the only "solution" could be a miraculous glow up that makes you become comfortable in your own skin and attractive enough to have a healthy sexual life.