Son has white spots on inside of lips?

My 8 year old son has been complaining about his lips being sore for a couple of days, so I gave him some oragel, and it helped temporarily of course, but the pain kept coming back, I didn't notice any spots until today, they are not visible from the outside of the lip, but they are tiny, splotchy white spots (not bumps), they are not on the gums at all, just inside of the lips. I can't help but think he may have come into contact with something on his hands, and transferred whatever it is to his mouth, or maybe some kind of virus? Thank you so much!