I upvoted a comment that I found intriguing. However, it crossed my mind again and I couldn't remember on which post it was. Is there any way I can find it? Or should I browse through my browser history?
No, unlike upvotes to posts there is no list of comments you've upvoted.
If you remember some words in it, you can use this SEDE query to list the comments with a score of 1 or higher and visit each one of them to check if you upvoted it. Please note that SEDE is updated once a week, on Sunday morning, so very recent comments don't appear in it yet.