GIRLS HELP: guy problems?

[princessbubbbles]

There's this really hot guy that i went to camp with and from the moment I saw him I thought he was attractive. BUT I only got the courage to talk to him the last day of camp. :/ after talking to him I realized we have a LOT in common. But since it was the last day and he had to leave I didn't get to exchange numbers with him. I found him on instagram and followed him and he instantly followed me back.. But my question is how do we exchange numbers if that's the only contact we have? Should I comment on his picture or something.? Leave my number for everyone to see? I don't wanna look desperate.. I just want to continue our good convo and be able to keep in touch