Possible side effects of laser legs laser hair removal are quite harmless and rare. If side effects occur, you should find that the latter only for a few hours, a few days. The most common side effects of laser hair removal are swelling, usually around the mouth of the follicle, itching, which usually happens during the actual treatment, laser hair removal, redness, which can typically last up to three days after treatment, and some bread. Remember that these side effects usually only temporarily.