Could Night Guard Be Causing Irritation in Cheeks and Lips?

Have some irritation in my cheeks and the inside of my lip -- could my night guard be causing this? I've worn this guard for some time but it seems to be getting worn down. I'm just hopeful that its the mouth guard and not some of the more horrible conditions i've read about online. The irritation is just some rough patches...and a little soreness in my lips. Please help.

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