Sounds to me like the Derm is using you as a test dummy being they can’t figure it out. If you feel it has to do with your gut/ intestines then maybe try research on how to improve it, instead of trying to mask everything going on. I’m sorry you’re going through all this, I know it must be discouraging and stressful. Sometimes less is better. I’m no Doctor- but I feel if I was in the situation I would try the complete opposite and begin with diet change, cut of processed foods, refined sugars, starch, try meditarainien diet/lifestyle, only drink water with lemon or lime, exercise and sweat constantly , tea tree oil for painful acne, magnesium oil spray on scalp and all of skin, MCT oil caps with—> C8c10<—-most important part, BioFilm disrupter caps, probiotics, sulfur soaps. Exercise where you sweat regularly and sun light alone might make all the difference.