Seems to me like your snake is due for a vet visit. RI in a baby is very serious and needs immediate treatment. The scale issue looks like a result of the bedding being damp too long, may no be scale rot yet but if left could develop into said. Clean the enclosure with a bleach solution, put down paper and see the vet for the RI. Once the RI is treated you should see the scale issue clear up as well and could go back to regular bedding but cut down on misting or whatever is keeping it wet.

What bedding is he currently on?

What are you measuring the temperatures with? Is it an undertank heat pad you're using? If so, is it on a thermostat? Is it possible that the belly got burned a bit at some point?

Or is it possible he has a retained shed? The humidity is pretty low. Have you tried soaking him for awhile to see what happens? What do his eyes look like?

I'm just trying to rule some things out with my questions... is it a slight whistling sound only or is he gaping his mouth? Do you see extra fluid / mucus present in the mouth?

I have had some snakes make a very minimal sound that was like a whistle / pop while in shed or with retained shed, so that "might" be possible. 

Are you able to take a close up / macro pic of the eyes with a flash - often that is helpful in determining a retained eye cap. Does he seem overall "dull" or is there a shine to him?

Only one of the two pics you posted is showing up for us. What was the first pic of?

They will make a wheezing noise when they are going into shed. If he does have a retained eye cap, just be sure to up the humidity to around 70% next time he sheds, and it should come off...