Why is my dog licking her paw?

This morning my dog was licking her paw for some time. She doesn't seem to be in pain and is walking normally. She doesn't have any allergies (as far as we're aware) and I didn't find anything that was stuck in her paw. She got groomed 4 days ago, could this have irritated her paw? I am a little worried about the redness. Is there anything I can do?