I'm trying to build muscle, but I'm being hindered by an old injury

I don't know enough about fitness to even know what I'm hoping to get out of this, but maybe you can help me figure it out. I've been lifting weights for about 6 months now and it was causing pain in an old injury to my forearm all along, but I recently went from 10 to 15 lbs (I'm disabled and even the 10 has been a lot for my body, but I'm getting there).

A decade or so ago I was shot with a (small) crossbow. It went straight through my forearm, between the bones and tendons, and pierced the median nerve without severing it. I suspect that the scar tissue is hindering my tendons though, from the way it feels.

I guess I'm hoping there's some sort of device that can help take the weight off my hand and move it higher up my arm? I'm already seeing my doctor about it too, but I have a wait for an MRI.