I would try to figure out a way to earn some money to get the injections
After all you did get her to the vet which means that you have a lot of initiative and spunk and can work on a problem until you resolve it.
When you are able to be around Caramel and can watch her I would take off the collar ..but when you have to leave (even for a few hours) put it back on.
Most buns do not do well with them but it sounds like you are on top of things by syringing fluids and food to her. You only need to do this for a4-5 days because once those sutures really close it won't matter as much if she chews out a few.
your parents are being sensible about the economic conditions of the family and that is understandable , however, when you love your pets it isn't easy being sensible about it.
Most of us are the same as you are and it will care for the pet no matter what ..
so to us you are a great person for getting her back to the vet when she ws in need of it.
Now start thinking of ways you can earn some $$$...babysitting, petsitting, going to the store for elderly people etc ..think about it
have a jar or something to put all extra change into as a fund to save for their shots
Maureen