Hi there and welcome.
The tiny lump could be a hernia or teste depending on where it is.
It is VERY important that you have him neutered because with his teste being buried deep inside his body, the internal heat can lead to all sorts of complications, not the least of which is cancer of the testicle/s.
I don't know about where you are, but over here it costs a vast amount more to neuter a crypt because it can be a really tricky procedure when them having to go in deep to find it.
In my opinion he'll be fine until Wed. but just keep a close watch and if it should get worse then get there straight away. There's a dog painkiller that's name escapes me at the moment that you could ask the vet to prescribe until you can get in there or, alternatively, they may let you pay on Wed. but see him before ... if they know you chances of that are very good. Do you not have a credit card you could use? Or borrow the $'s from someone?