Do the posts you upvoted show up somewhere?
I upvoted a post, where does it show up?
No they don't, you'll have to but you could go your profile, go to your comments, and then check the posts where you commented. Those posts are most likely upvoted (according to my past experience, not 100% true though).
If you wish to see this feature implemented, suggest it in feedback here.
But I don't think they'll be a very useful idea because why would you need it? :)