The reason to stay out of the sun for a few weeks (3-4 weeks) after your procedure is that the incision sites are healing and are at risk of pigmentary changes (hypo or hyper-pigmentation). Sun exposure can worsen this potential change.The reason to stay away from swimming in a pool is that the incision sites are healing and exposure to pool water (which is far from sterile) puts the incision and the wound at risk for infection.