Itchy bumps for a week now after going biking w/ sunscreen. seem to be clear/flesh colored until i scratch them and they turn red. is it heat rash?

Maybe: It is possible, depending on location of the bumps/rash. Areas under clothing or heavy perspiration are potential sites for such rashes. If on outside skin areas where sunscreen was applied, may be assoicated with contact allergy to the sun lotion or its preservatives contained. Do not scratch them. You may try use of 1% hydrocortizone cream (cortaid) applied 2-3 times a day... No scratching.

Could be: Is very difficult for us to make a diagnosis without seeing the lesion and having more information. If you want to have an accurate diagnosis, you should contact your primary care physician.