how do i respond??

so… a famous doctor (social media is his other job) dmd me but he only dmd me a “:)” and i wanted to respond so badly because he’s been my celebrity crush for like ever but i have nothing to say to a :) LOL. i liked the message and never said anything else and we don’t follow each other but we both live in NYC so i want to say something but my flirting skills suck. pls help 🥲