So these dark red spots I've been getting in my mouth. They come and go. I ate some skittles now I have a red spot and its bleeding? Idk. Inside cheek

Needs evaluation. Anything swollen, discolored, bleeding, out of the ordinary should be examined. 5 most dangerous words in the english language, "maybe it will go away.".
CHANGE. Change your food and see what happens . Keep mouth clean and if it worsens, see a dentist.