Help, my Bearded Dragon has a weird Skin Growth

[M.c.K.a.y.l.a]

Hi, I own a very plain Jane beardie. He is three years old and his name is Stitch. I got him from a friend for free. She got him from a terrible breeder who didn't feed them and unfortunately, his brothers and sisters chewed off the end of his tail, some toes, and up to the elbow of his right front leg when he was a baby. But he is happy now! But my problem is since I've had him, this bump that looks like it is shed that has built up. Just this past week it has turned a tad white on the end and the skin around it has turned yellow. I touched it and he flinched slightly. I haven't been able to take him to a vet because there are none around me who do reptiles. I was wondering if anyone out there had a similar problem and if it is lethal I am willing to make the drive to a vet. I will include some pictures, if anyone knows please let me know.