I do an infrared sauna daily and last week I got a gash in my arm which is a little like surgery!! It has been 4 days now and when I go into the sauna with it it starts to hurt quite a bit. So I wrap it up in a thin cotton towel so the rays don't get to it and it feels fine (infrared rays don't go through the material). So I think you have a way to tell whether you should be in the sauna or not...your body will tell you. And, if necessary, cover the body part in question.

If it is major surgery you may want to start with 1 or 2 minutes a day in the sauna and then gradually work up according to "what feels perfectly good"...never pushing yourself to stay in if you get any pains or dizziness or anything short of "feeling fine" in there.