I really doubt that it's inexperience...
Those look like deliberately inflicted injuries, and not from a rat. Unless the mouse or rat decided to drag their teeth along...ugh.
It looks like she tried to 'help' him shed.
Kudos to you for nursing him back to health.
(I should probably go, Cap is glowering at me from his hide. Is he angry or jealous that I'm looking at bigger pythons? Ha!)