Working out and sweating should not be a problem, however, it is normal to have transient redness and swelling after your treatment. This usually resolves in 24-48 hours but can take 3-5 days. Bronzing, or brown debris on the surface of the skin is a side effect that usually occurs a few days after treatment. This is normal, even desired, and will resolve over the next several days. These side effects can cause social downtime for some patients. In the gym, you will want to avoid anything that irritates your skin: i.e.: harsh cleansers, rubbing your face, using a sauna or steam bath...Your practitioner should be able to recommend a skin care regimen for you to use immediately post treatment. As an informative side note, using any kind of systemic steroids would be considered exclusionary for anyone seeking 1540 fractional non-ablative laser treatment.