I just noticed that Cosmo's nail is dark brown at the tip area. I have some pics of it attached below. I tried taking the best pics I could but Cosmo is a bit camera-shy and she always moves away from the phone If anyone could tell me why it's there, and what it even is, that'd be great.
Should I clip her nail then, or should I go to a vet? She is not that tame, and probably won't let me do it...
If you are uncomfortable/nervous doing it yourself, I would suggest going to the vet where they can show you how to clip nails properly. You could also get them to examine the discoloration on the one nail to rule out any issues and put your mind at ease. It can be tricky clipping nails for the first time, and you have to be careful that you don't cut into the "quick" (vein) that is in each nail, otherwise it will start to bleed. The quick is pink/red and you can usually
see where it ends partway down the nail.