My dog has scars on him and he is not abused. He is just a poo poo head with other dogs and also when he was a pup he tried to dig his way out of the crate. Sometimes the rubbing on the face against the metal bars can cause hair loss and eventually scarring. Since he is so personable with people and not afraid I am not so sure I would jump to the conclusion he was abused. That does not mean he wasn't, but every dog that someone gives up with a scar was not neccessarily abused in any way. I am glad you have him now and it won't be an issue.
I was thinking the same thing…maybe he wasn't abused. He may have been anxious in his crate and cut his face on the bars. The other thing is that some head halters if not fit correctly dig in and wear fur & skin down. Doesn't mean he wasn't abused, but there might also be another explanation.
It is hard to second guess what the cause is and what the marks look like...maybe post a pic when you get a minute.
Oh, and to Jinxed...welcome to the forum!