Slow down a whole bunch so you give yourself a chance to think of melodies rather than boxes and scales.

Try singing a melody to some backup music into a tape deck, then copy what you did on guitar. Even better, use recording software and do the same thing.
That way you can divide the melody up into smaller parts and loop them while you copy the melody on a different track.

Try using some alternate tunings. Play the riffs and scales like you normally do and record them, then tune back to normal and learn what you did when you had your guitar tuned differently.