I'm a poor college student, money is always tight and I have 5 pigs! Here is what I did when I got my first pigs in case something like this ever happened: I "shopped around for a vet". By that I mean, I found a very good
cavy savvy vet at prices that I could afford. Just for the vet to do a general health check is $38, and for a neuter and everything associated with it was only $116 (he got free check-ups at the place I go to). They know I'm a poor college student, and I guess they really care about the animals and that I do everything I can to do right by them (the guinea pigs). I also made sure that if a bill ever gets too high for me to pay right away, that I can make payments until I've paid off the treatment.
Here's my point: are there any other good
cavy savvy vets in your area or that you would be able to get him too that is MORE SO in your budget? Also make sure that if necessary you can pay in installments. I know for me, doing this makes having 5 pigs MUCH easier financially and I have peace of mind. You can also ask them for an estimate on the phone so you can compare the prices at places.
Until then, make him comfortable as possible, restrict his movement and watch him closely.
And please do not take this last comment the wrong way, I mean NOTHING negative by it. Next time when spending lap time with your pigs, make sure they are on your lap, not your shoulder just in case something startles them. I know how jumpy they can be.