While my guitar skills are below average I am an active musician who has been playing for 25+ years (20 of those semi-professionally). It all comes down to practice. If you don't use it, you lose it. In my case, I used to play keyboards in a band but when we folded 2 years ago I haven't played since. With regards to your situation though, I do play a stringed instrument of sorts in another band and the same principle applies. Practice whenever you can, just sit down and play along with a song you like. Even if it's basic bar chords to start. Learn your chord positions and inversions if possible.
If you really want to forward your music, sign up for some basic musical theory courses. I took musical theory for 2 years and it did wonders for me. I wouldn't be the musician I am today without that.