Advice needed

I "rescued" an albino feeder mouse from the pet store. She is obviously very young (I'd guess maybe 18 days). She was getting run over by all the other mice, was puffed up and just did not look good. I went and got KMR and been feeding her off the end of a spoon (the dropper did nothing). She made it through the night and each day looks better and better.

There are two problems though. One, I haven't seen her once use the water bottle (she is eating solid food). Two, I think she may be blind and deaf.

I have dogs and when they bark, she doesn't even flinch. She doesn't seem to hear the cage open or any other noise. Also, if I put my hand next to her, there is no acknowledgement. If I lightly touch her, she jumps like I've scared her (which I probably have as she had no idea I was there)

Now comes my question. I was planning on getting her a companion (I have rats, not mice). Now I'm not so sure. I'm afraid it will stress her out that this other something is always touching her (sneak up on her). Do you think it would be a good or a bad thing to get a friend?

She will need a friend, but I would not suggest "rescuing" another feeder mouse that's that young. O.O If they're not fully weaning these mice, they're bound to have serious health problems, and they might be better off being humanely culled and fed to a snake than having to live out their lives that way.