Time. Believe me I had that issue. Lasted me six months (no joke) but the pain got better after a month or two so I could continue to work out.
Eat lots of clean carbs, protein (yes up your carbs and protein for a while). Make sure you sleep as much as you can. Stretch the arm by grabbing your palm and stretch upward it should look like your fingers are pointing up like a line.
And believe it or not you need to work your forearms to pump some blood flow to heal it works trust me. 15 to 20 reps of wrist curls, forearm curls reverse curls do them for like 4 sets (take it easy for a while) then when your body gets use to up the sets to 6. THEN closely up the weights and with time and healing your forearms will be indestructible after this trust me.
I put my forearms through hell and back and more and they ain't feeling pain only growing. Good luck brother.