Hey twinkles,
I am old enough to be your Mom, and I have had one going just below the corner of my mouth on the side of my chin!
In my case, I do not have acne, but, once in a great while one of my pores do get clogged up. Sometimes is can be deep within the skin where it will take it some time to clear up, either from the inside, or the outside.
Don't know what to do, except keep your skin very clean. In my case, my skin can be a little sensitive and dry. So I would always avoid any cleansers or medications that would end up making the situation worse. Things like strong cleansers, scrubbing pads, etc.... For me they make things worse!
I use a completely oil-free base make-up that I love that never causes these... L'oreal Mattique. It TRULY is oil free. ( I have tried others that felt like crisco on my hands and face!!!) Some may say 'oil-free', or acne medicated... I would take those words with a grain of salt. On a budget, this really is a 'clean' make-up.
Hope it gets better soon!