I have to say, I would not be very happy if my guinea pig was in a vet's care for 3 or 4 weeks. This is a lot of time in a guinea pig's life.
Could there not be some way she could be with you?
This is the medical topic you started on this guinea pig:
Perhaps you can post on that topic detailed info on what treatment was given and what your guinea pig is now getting to treat the ringworm.
- Supporter 2016-2020
As to your healthy pig, put her cage where she can see and hear people, talk to it often and as you are doing loads of cuddles. But I would NOT get another pig! What happens when the one at the vet comes home? The longer the one at the vet stays there the more likely they will forget each other.
Maybe one of these vets is near you or you current vet could get in touch with them? http://www.guinealynx.info/records/viewtopic.php?f=77&t=277
Hoping your piggy comes home soon. Sending healing vibes your way!