Ultimately I think the broader concern you are facing is the chance they discharge
you based on this medical problem. If you have a medical issue that prevents you from training (in any MOS) and is expected to last one year or more, they Marine Corps will separate you.
I would expect them to explore this option based on your recent injury.
To answer the question...is it possible to "switch back" the answer is sure...that is possible. But not likely. Not at all. If the Marine Corps took the time to send you to a separate A school and you were injured in that school, the first thing the Marine Corps is going to do is ensure that you are physically able to continue to be a Marine.
If they find that you able to serve as a Marine, then I would expect them to send you back to A school (ITBn) That is since this is now your slotted MOS.
Can you request to switch?
Again, yes...but you have an uphill battle. This is now a MARFORRES issue...so it has to go to the general for approval.
Your immediate commander can certainly make this request...and if there is good reason for the change, I would expect MARFORRES to consider it.
You mention that there are work issues that now conflict...I would focus on that. I would focus your request, to your CURRENT COMMANDING OFFICER
, on the civilian job conflict. That can be grounds to modify back
Again, they made the chance...MARFORRES made the change to train you as an 03. TO change back you will need a reason that is not tied to your current physical condition (since if you are not physically qualified, they are not going to keep you in any MOS)
Let me know if you have more questions...happy to help if I can