Painful hard lump still in cheek above infected tooth after abscess drainage & root canal finished. how to get rid of this swelled area day 4 on meds?

It'll take a while: Sounds like it was a severe infection. It will take 4-6 weeks for swelling to go down. Pain should go down by the end of antibiotics. If it doesn't then a scan to see if infection is still trapped in sinus cavity is a good step.

Time: It takes time for this to heal. After an i and d, it is normal to have a hardness in the incision area. However i recommend you get checked to make sure.

Be patient: It may take some time (10-14 days or so) for the swelling to go down significantly. Try rinsing frequently with warm salt water and apply moist heat 3X a day. Take NSAIDs OTC for swelling and pain control. Good luck.