Missing scales?
 

I'm sorry if I'm not posting this in the right place.
So a few weeks ago I noticed that some of the scales on my 1 yo corn snake's belly've turned brown. I immediately took her out of her enclosure to take a closer look and found out it was just some stuck dust/dirt? I was able to remove it and didn't think much of it. A few days later I realized that the reason she gets so much dirt stuck under her belly scales is that they're chipped. They also felt dry and kind of sharp, some were sticking out. I think the humidity in her terra is ok because she had a great full shed just a month ago.
I had to leave for a few days and when I came back today I noticed that a few scales are missing and the skin underneath is reddish. I'm really worried, could it be scale rot? It could be from the substrate I'm using (wood chips)... Should I change it? I don't think there are any sharp objects in her enclosure. :cry:
Apart from that, she seems healthy. I just fed her (never refuses a meal), pretty active, good shed, not aggressive.
Sorry for the poor quality of the photos.
https://serving.photos.photobox.com/...4eb6bafce9.jpg
This is the kind of substrate I'm using
http://prikachi.com/images/386/9325386w.jpg
http://prikachi.com/images/387/9325387B.jpg
http://prikachi.com/images/388/9325388L.jpg
This one worries me the most... you can't really see it in the picture but the skin underneath is pink...
http://prikachi.com/images/390/9325390r.jpg
near the bottom
http://prikachi.com/images/391/9325391C.jpg
http://prikachi.com/images/392/9325392t.jpg
Thank you for ur answers in advance.

It does sound like scale rot, but a good veterinarian can give you better information. I have seen scale rot, but thankfully not on my snakes. It is usually caused by too much humidity, wet substrate, or bacterial buildup. It is good that you noticed it somewhat early. If you want to try to treat the condition, assuming it is caused by bacteria, I'll tell you what others have told me when they treated their snakes.

1. Set up a quarantine tank or enclosure, with proper heat gradient. Use paper towels instead of substrate. Use disposable hides, like paper towel tubes.

2. Clean the affected scale areas at least daily, using Betadine solution. Some have used Clorhexadine. You can briefly soak her in the lukewarm, 82 degree solution, but she probably won't like to stay in it very long. After treatment, rinse her well, dry her and apply triple antibiotic cream (without pain killer additive). Some have had good results using 1% Silvadine cream (silver sulfadiazine) Ask your pharmacy for the correct Betadine solution mixture. Some use 1% and others told me they used 10% mixed with water. Hope the items are available in your area.

3. Clean her original vivarium with a good bleach solution, after throwing out all the old substrate. Clean and disinfect anything you intend to keep in the vivarium, like hides.

4. Keep up the treatments until she sheds again, and see if the problem has been resolved. If so, she can go back to her usual vivarium. I wouldn't use those wood chips as substrate.