Welts under my skin.

Quite often, I get giant welts under my skin. They come to a head after a couple of weeks, but not like a normal pimple. They grow scabs even with the slightest touch, and appear only on my cheek bones at the very bottom of the sinus area under my eyes. They drive me crazy, it looks as though someone punched me (that's what everyone asks). I wash my face/exfoliate, and have never changed product, but for some reason I get these at random. They also appear on my nose, in the small area on the bottom side near my lip. Any ideas what this could be, or what causes it? Maybe an allergic reaction?