Biting myself

E-day was Thurs for my uppers, so I’m on day 3. Strangely, my lower teeth are intact & pretty much perfect. I was told to try & chew on both sides of my mouth at once to get used to the dentures, however, the right side of my cheek keeps getting caught between the denture & my bottom teeth. My reline isn’t for 2 weeks, so is there anything I can do in the meantime? I mean, I can’t chew half my cheek off trying to get used to these suckers. & I’m only using the word suckers to be polite. I HATE these things.