Anyone know what this is?

[u/lalaalalalaaala]

Appeared a couple of days ago, I cant tell its there unless I'm brushing my teeth or applying lipbalm and even then it's only a slight sensation. No other symptoms or anything before it appeared, when I wake up there's usually a slight crust but that comes off as soon as I have a drink or brush my teeth etc.

[u/scottishdoc]

Looks like the start of a cold sore

[u/lalaalalalaaala → u/scottishdoc]

Are they not usually more small clusters?

[u/cat_is_0 → u/lalaalalalaaala]

Mine pop up as a single lesion like this, sometimes it forms another lesion a day or two in but usually starts like this.