Only have my mustache grows, what can I do?

I have always grown a full mustache but mine started disappearing little by little. I only grow one side and the other is as smooth as a babies bottom. what sucks so much about is that I have to keep up with shaving one side so you cant see it growing in and looks like I forgot a side lol. (what’s going on) any anwsers

A mustache transplant can solve this problem, something we do frequently