I can't say if that is or isn't the beginnings of scale rot, but...
A few months ago my lesser male had some scale rot and all I did to fix it was put him on paper towel and make sure everything was very clean and DRY - no misting of his enclosure etc, I just used a humidifier to make sure the air itself was humid and nothing in the enclosure was damp or wet. I replaced his regular water dish with a tiny one that he couldn't crawl into. Then every day I took a piece of gauze with Betadine on it and wiped the area clean. A few weeks later he shed and the scale rot was completely gone with it. (Thanks Deborah for this advice!)
If it is scale rot it doesn't look bad yet so you don't need antibiotics or anything serious yet. Just keep it clean and see if it comes off with his next shed.
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