Thank you for all your helpful replies! A question for anyone - would it be ok to wait until Saturday to take her? I want to take her to Taverham as it's the one I've been using for a bit. I'm just afraid any vet I'll see will automatically go or after a bit of dawdling, "put her down, it's the kindest thing to do as guinea pigs aren't big and don't take to operation." or try to extend problems for money. Etc.

It's a fear I've had for ages as many vets seem to take the quick route to pts.
Thanks! Can I ask how it was and who you saw for it? I'd spay her to hopefully be somewhat done with it but I don't think there's a vet I'd trust to see a gpig sow spay through.
Thanks for your reply and RIP Ellie
A question or two if that's ok

I didn't know they bleed after the injections, is that a thing I missed? Also, hope you don't mind me asking, but did the cyst and/or injections for it have anything to do with the later health issues?