Hi there! Do you mind sharing your routine with us here?
Tbh if the cysts are active, red and irritated, I wouldn't recommend to exfoliate, but in general, if you feel the need to exfoliate, you probably should :) Start with a gentle exfoliating toner few times a week or a peeling/gommage once a week. Consistency and patience are key.
Sheet masks are usually applied after cleansing the face, but whether you want to use a toner/ampoule/essence/serum before the sheet mask is entirely your decision. It also actually depends on which product and sheet mask you intend to use one after another, since you don't want the ingredients of each to cancel out or react with each other. Hope that helps ☺️❤️