Yet another "Scale rot??" question

[Bogertophis]

That's looks to me more like excessively dry scales & possibly some heat damage (pre-burn) from UTH use, rather than "scale rot". Are you taking the temperature over the UTH & where the snake actually can touch the glass? -or just relying on what the t-stat says it is? Because those readings are probably different, & if you're counting on a snake to not dig under the substrate, well, that's what they do. Yes, BPs can be clueless about letting themselves get too warm- perhaps because they're more heavy-bodied, they don't realize damage is occurring until it's too late. So as their keeper, you have to do their thinking for them, lol. And yes, a pinkish belly can be a sign of impending shed, but it can also be a "burn". It's critical that you take the temps accurately & adjust them- A.S.A.P.

Re using diluted Betadine, no, you never want your snake's head in that, they might drink some! Avoid soaking anyway, it's stressful, & overkill for what you're trying to do. Just dab the solution on topically, if needed for an infection. You'd want about 3 parts water to one part Betadine, & never let a snake ingest it, please!

IF you needed a topical antiseptic, you're better off using the water-based* Vetericyn ointment- it's FOR snakes, whereas ointments made for humans or warm-blooded pets are petroleum based, and that WILL mess up your snake's future sheds for a while IF you use much of it.

Aspen substrate stinks for BPs- it's dehydrating, it holds no moisture that BPs require- you need to fix that, & /or offer a humid hide (warmish side).

The "cool side" of tank is WAY too cold...you did say you were fixing that??? For a snake to heal from ANYTHING, or just to stay healthy, the temps are MOST important because their entire metabolism depends on temperature. OK?