Has anyone ever experienced this?

So basically, I'm lying in bed watching tv and just finished my ice cream. I licked my lips y'know like you do, and something felt odd. I felt a little lump so I went to my mirror and had a look. Yep, a little lump. Not in the middle just to the left of the middle. I went downstairs and shown my partner thinking I was probably getting a cold sore even though I can usually tell when I'm getting one. I didn't feel a tingling in my lip or anything, I only noticed it because I licked my lips. Then after about 5 minutes it was gone!!! What?? Should I be concerned? Does anyone have any clue what it could be?? Tia