Should i hire a lawyer in a work comp case even if my employer picked it up as a work injury?

I hurt myself at work. Went to ER and had a herniated disc in my neck. Put me out of work n was told to see a specialist. I went to my pain management doctor n they confirmed my herniated disc n wanted me out of work. Told work n they wanted me going to there doctor. There doctor told me i was lying n it was a pre existing injury. N tried to make me go back to work. I refused n went back to my original doctor and she put me out again. In the mean time it was the holiday n no one was around to answer questions. After 3 weeks I reached out to a lawyer to represent me. (I was on a lot of meds) not sure I made the right decision. Went to work with a new note n my boss told me work was excepting the claim. So is a lawyer needed? How does that work? I signed something about they get 20% but 20% of what? My weekly wages?