together even if the normal is to do a group thing.
My wife never got asked to prom and it makes me sad for her. This is what I'd recommend
1) find a girl, ask her to the dance.
2) try to find a group. Mention it to her you don't have a group, and maybe she has a friend group that will let you in.
If you don't find one, take her bowling or on a "day date" of your choice. Then take her to dinner before the dance. Hang out at the dance, and have a good time. If you need to leave early because you/her get bored that's not the worst thing that could happen. Be a respectful young man and you'll be glad you went.
I know what it's like to be in your situation. My friend group blew up at the end of my sophomore year. The girls in the group all moved to different cities/schools. I spent my entire junior year working and lonely. I met some excellent people during my senior year who took me in.