I actually can't tell what you are talking about from that pic.

I'm more of a lizard girl (in the process of becoming a snake girl...) and really scale rot shouldn't be happening with beardies. Correct me if I'm wrong, but it's generally humidity related and beardies shouldn't have a humidity percentage over 40. 30% is really much more ideal.

I'm betting on retained shed, nasty former cagemate, beginning of a shed, or possibly yellow fungus.

I wouldn't soak with hydrogen. Especially when you aren't sure what it is. A vet might be good. He looks young enough that if it's not bugging him, you might just want to sit it out through another shed and see if that changes anything.