Thrush?

I don’t know what this is but i noticed it after took my clothes off to go to bed last night. Plz help? I think it’s just from my underwear rubbing but I’m not particularly sure. Its not exactly itchy but Ik it’s there so it’s bothering me. {it’s a lot more red and irritated than it looks in this picture}

My friend said it might be a food allergic reaction...?

•UPDATE•

It’s still there, it hasn’t gotten any worse but also hasn’t gotten better. I took a yeast infection medicine last night and I’m gonna give it a few days.