4 months after FL my face gets extremely red when it's hot out or after I exercise. Is this because I am still healing?

The hyperemia you're experiencing during exercise and overheating is very typical in any area that is healing after surgery. This will correct itself over time as the inflammation subsides.

Dear imagingboomer,Yes, you are still healing. Please keep in mind that driving,
exercise, and other activities that can cause a strain on your muscles need to
be avoided for at least one week and potentially longer, depending on your
personal healing process. Consult the board certified facial plastic surgeon who performed your surgery with any concerns in your follow-up appointment.Sincerely,Ross A. Clevens, MD, FACS

You are correct in your assumption. At the 4 month mark you are still healing from the facelift and most probably what you are experiencing is the redness of the healing process still showing. Check with your physician because this should be only on the areas of the surgery. If you are getting red around the central area of the face, this might be another condition of problem like Rosacea. take some pictures of the problem when it happen and show them to your physician. you will help in this way to make the best diagnosis of your problem.Hope this helps,Dr. Gus Diaz