Had 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.

Dermatitis: Whether heat rash or reaction to the sunscreen, you seem to describe a form of "dermatitits". Itchiness, color change and bumpiness are typical of "contact dermatitis" and responds to eliminating the offending challenge, either sunscreen and/or sun. Calamine lotion and/or otc Cortaid (hydrocortisone) (steroid cream) may relieve your symptoms.