Is this baby teething rash?

Could be or could be from the sun or an allergy. Just keep it clean and moisture it regularly

I breastfeed and had to go away this weekend just gone, so the baby had formula for 2 days, and when I come back, she had a rash on her chin and cheeks that looked similar to this.. went back to breast feeding, so no more formula and it was gone within 3 days... I think it's probably a dairy allergy, I only say that bc I don't really consume any dairy at all and it came and went so quick