This question from Sean about a sore tooth is a good example of what happens when something hurts or feels funny.
It makes you want to look in the mirror to see what the problem is.
You notice things you never saw before.
And it can be worrisome.
Hi Sean, I can't tell you for sure, but there are a couple of possibilities.
The loose, sore tooth could be from clenching and grinding your teeth. This habit almost always occurs while you sleep and most are not aware of it.
You will have a better idea if you keep noticing the same problem.
Once you are aware of this possibility, it's easier to know for sure.
You can read more about teeth clenching and grinding here.
The red band could be the normal color of your gum tissue.
Gums are normally light pink near your teeth and higher up (or down for your lower teeth) gum tissue looks red.
There is usually a line where the pink firm gum tissue ends and the redder cheek tissue starts. You probably never noticed it before because you never had a reason to look.
If you are concerned or if you have any other symptoms a quick trip to the dentist will be helpful and is the only way to know for sure.
If either problem gets worse, or doesn't resolve in a few days you should see a dentist.
Hope that helps,