Why don't you try playing by ear (if you aren't already). It really helps you pick up on what the guitarist is doing on the fretboard, how one phrase leads into another, where certain things (bends, vibrato, whammy bar, etc.) sound good/bad, and hey, at the very least you can steal some licks!
Another thing you can try is taking a backing track, play the song with it until you're comfortable, then try making variations, doing your own thing. Start off with the song to get yourself going, and don't force yourself to improvise- just let whatever happens happen.
Note: pents are great, but they're not everything. Kirk Hammet uses 'em like crazy, but guys like Satch, Vai, Petrucci, and the rest frequently to either the major scale, or scales based on major. Now would be a good time to start practicing major scale patters as well.