Open Question: Workers compensation concern, help please?

I am a server at a chain restaurant, and last night I was putting a drink tray back on the rack when my elbow popped. I tried to shake it out but realized that it wasn't working and became quite painful as time went on. So I immediately told my employer that I can no longer work because my elbow really hurts. So I filled out an injury report and they gave me a Workers Comp form to fill out and I told them I have to get it checked out at the ER. Long story short, the ER doctor said its just Tendonitis/Bicep tendon sprain and gave me a sling and prescriptions. However, he also gave me a note for a week off of work starting today. So strangly enough, I woke up this morning in absolute no pain, took my arm outta the sling to stretch it and just to check it out, and everything feels 100% normal, I even did a few push ups to test it out. Full strength and mobility, almost like nothing was wrong last night (even though i was in tons of pain at the ER last night) Is it possible to return to work earlier than the doctors suggested return date? Would I be able to call him to tell him I am ready for work or will he have to evaluate me again? (I don't want to run up the bill on my employer either, workers comp thing...)