4christ, you don't say what State you live in, but in Oregon, if you are injured at work, you have the right to go to ANY doctor ANY time (and not limited to ONE visit or ONE doctor), explain the cause of the injury, and the Worker's Compensation Board takes it all from there. It is solely the determination of the WCB that prevails...you need not get an attorney to defend your rights. All due compensation will be paid retroactively to the date of injury. If you disagree with the initial determination of the WCB, you have very specific appeal rights.
I'm not a specialist on WC law, but I HAVE been through several operations (I am a construction worker too...hahah) and on WC for a combined period of over 2 years. Never had a problem like you describe.
Also, I suspect that the employer may be liable for discrimination and violation of State labor laws. Perhaps others have more certain knowledge of this.
Peace,
Craig