Pale, greyish gums can be some really bad stuff. I'm glad it is not, and your girl is ok. I would have said check her other vital signs, is she running a temperature? Does her skin spring back when you pull it on the top of the neck? Can you push the gum so that it is white, and how long does it take to refill? Is the nose wet or dry? Had she eaten today, is she drinking, did she poop? That sort of stuff.
But sometimes paying for peace of mind is good money spent. I have been known to take one of mine in because she just seemed a bit off.
Some of the things that will show pale in the gums, and people who know more than I can correct me if I am wrong, but I think hemangiosarcoma can, if she is bleeding out; bloat; heart problems -- most of these though are when the dog is in an emergency crisis phase. So if the vet checked your girl out, and the gums are back to normal now, it is unlikely for any of these to be a problem.
Jenna, RN CGC & Babs, CD RA CGC HIC
Heidi, RA CGC
SG3 Odessa, SchH1, Kkl1, AD
Ninja, RN CGC & Milla, RN CGC
Joy, Star Puppy, RN CGC
Dolly CGC & Bear CGC