I had surgery on my foot a week ago.today i woke up with a painful, itchy rash that started on palms but has spread all over. what could it be?

Ck your post op meds: If you have palmer rash from post-op, and were placed on antibiotics, or other meds, you must consider if this could be a possibility or not. In either case, contact your foot doctor, or surgeon, and let her/him know about it, so they can advise you further. This is best done in person. You don't want this getting out of hand, and compromising your health.

Rash: See the prescribing physician as this certainly sounds like an allergic reaction.