Took a 5-day z-pack post wisdom teeth extraction & and recently finished it. I now have a face rash w/ little red bumps. Why/how can I get rid of it?

Face rash. Check with your physician. Sounds like an allergic reaction to the z-pack. If so your physician can prescribe meds to combat the reaction.
Allergic Reaction? You may be having an allergic reaction to the antibiotic or perhaps an infection has started? Either way, you should see your dentist as soon as possible. Don't just wait to see what happens.