If you are assuming you have impacted ear wax because you have muffled hearing, that might be because after your middle ear infection is cleared by the antibiotics you can still have some fluid in your middle ear that causes muffled hearing.

I would complete the course of antibiotics, and if you are still having symptoms 3-5 days after completing the course, return to the office to have them take a look again. If you do have fluid left in your middle ear, they might suggest decongestants. If you do, in fact, have impacted cerumen, they can help clean it out.

I would be surprised if you truly had impacted cerumen. Most likely the provider was able to see your ear drum to diagnose you with the middle ear infection for which you were given antibiotics, which they would be less able to do if you had impacted cerumen.