When adult acne appears this can be one of the "areas."  I'd recommend finding an adult acne regimen - and you may have to try a whole bunch - even if it's just to spot treat that area - and give each treatment regimen about 6 weeks befor you decide it's not working.  Proactiv, Murad are  popular - so is the DDF line.  also make sure that your cell phone and home phones are cleaned daily with alcohol since you may be exposing yourself to bacteria from those surfaces and exacerbating the adult acne in the mouth area.  Some adults do have to commit to low dose antibiotics and prescription strength benzyl peroxide or salicyclic acid products as well to get it to clear up.