What is this small red rash next to my mouth? (Photo)

I just spent 5 days in Cancun Mexico and on the last day i noticed a small bump on my face and by the end of the day it turned into a rash. there is no itching or burning but it's a tad sensitive. it hasn't spread since yesterday when i saw it. i'm worried that it could be a disease or illness. i have been putting dermatitis cream on it hoping that it's just dry skin from the sun or salt water but i just want to be safe.. if i don't find any answers i will be going to my doctor!

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