I've been playing an acoustic guitar consistently for about two years, and I've reached the point where I can play full barre chords at a proficient level about five months ago. I was able to play full barre chords in songs (F, Bm, F#, and Gm in Love Me Tender, Pretty Woman, and Winds of Change) at a very proficient level. However, my barre chord skills have regressed after I stopped playing a guitar for about two weeks. I mean, I can't even play individual barre chords. I always get a mute string or two. Any tips? Thanks.
You just have to regain your finger strenght. As long as you continue to play, this isn't going to be a problem for long, I'm sure.
Also, you can try to see if you can shift your finger up or down so that the joints on your barre finger does not come directly above a string. This has a tendency to mute them because it's difficult to press down with the same force at the joints.