Blonde Bobby pin - I’m brunette 😔

Found a blonde Bobby pin in my boyfriends bathroom today. Asked him about it as I was leaving - he got super flustered and said it was probably his uncle (who lives with him) girlfriends, but she is also a brunette.. after I pointed this out he said he has no idea who’s it is. so I left. This was 5 hours ago and He has not even messaged me. I’m afraid this might be his ex’s, they had a very long relationship before me (1.5years ago) and have a dog together he takes multiple times a week.

I don’t want to sound crazy nor to accuse him of anything he hasn’t done because he’s a genuinely nice guy. But what the f do I do??