My sister has been struggling with it since young. We spent so much trying everything from tcm to western but it didn’t work until one did made it go away completely but it took her at least months to see the result. Initially it gotten so bad we almost told her to stop but my mom took it first and it helped her so she told her it’s purging effect and true enough after that it slowly clear up.
Funny thing is the things she used to think she can’t eat and she can now and it won’t aggravate her skin. So don’t give up.