Retin-A stretch marks formulations may also initially cause skin to flake off and the treated area to become irritated
. This is normal, but if the skin does not become conditioned to the treatment and 'settle' or stop flaking after a week or so, you will need to see your doctor or dermatologist to evaluate whether you need a weaker formulation or to stop the treatment altogether. You may also experience sensitivity to sunlight, and so it is recommended you avoid direct sunlight on the treated area, or use a strong UV protection sunscreen on the treated areas in situations where sunlight cannot be avoided.