Totally normal on the belly scales. They are designed to be flexible for gripping. Glad you figured out the trick to calming down your bitey corn! My adult corns are all on rats. They are "rat snakes" after all
If I had them on mice I'd have to feed them 2-3 mice a week to fill them up, easier to just do one good sized rat and they have no problem wolfing them down. It does sound like your corn wasn't satisfied with just the mice.
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Have you been hugged by your snake today? 
Ball Pythons
1.1 100% het Caramel Albinos (Edward & Bella)
0.1 66% ph Caramel Albino (Rosalie)
0.1 Caramel Albino (Bellatrix)
1.0 Butterscotch Ghost (Nick)
1.0 Honey Bee (Aragog)
0.1 Pastel Orange Ghost (Nagini)
0.1 Spider 66% ph Ghost(Nymphadora)
1.1 Mojaves (Lucius & Renesme)
0.1 Pastel Lesser (Narcissa)
0.1 Pinstripe (Arwen)
1.0 Pewter (Salazar)
0.1 Bumble Bee (Alice)
0.1 Lemonblast (Luna)
0.1 Blond Pastel (Katie)
1.0 Bell Pastel (Jasper)
0.1 African Dinker (Esme)
0.1 Normal (Madame Olympe Maxime)
0.0.3 Baby 66% ph Caramel Albinos (Edward x Bella)
0.0.3 Eggs in the incubator (Jasper x Esme)
Corns
1.1 het Amel, Anery, Charcoal, Bloodred (Romeo & Juliet)
1.0 Blizzard het Bloodred poss het Anery Lav (Tumnus)
0.1 Anery Lav (Lucy)
0.1 Plasma (Victoria)
0.1 Opal (Jewel)
0.0.22 Babies (Romeo x Juliet)
0.0.18 Babies (Tumnus x Lucy)
Hogs
1.0 Albino Western (Hogwarts)
0.1 het Albino Western (Hufflepuff)
0.1 Tri Color (Molly)