From what it stated in my file - and the one experience I had here - it seems that if I try to heal somebody, I will take partial damage myself.

The example I tried was a man had cut his hand. I healed it but the wound appeared on my hand instead, just not as bad. I'm not sure yet of the extent of how much I can heal or how much I'd be injured in the process. It did say that I couldn't heal diseases or cure death. So I believes it will work only for injuries, possibly internal as well as external.