If you can make straight time sound good outside a song you are a long way to 'being back'. Its easy to hide in a song....nearly impossible outside of one.
Set a metronome...play quarter notes while recording for 15 minutes(this is FAR harder than it seems)...check the recording for flams between the hits and 'nome...rinse, repeat at different tempos until you are getting through without too much cringe(note: your level of inaccuracy that makes you cringe will decrease as your ability increases...so motivation is key))
Move to pattern once you have really internalized the 'nome...but keep the practice/analysis cycle going.
Make a few recordings a day and analize them ruthlessly THE SAME DAY(in proportion to the gains you want to make)
If you go serveral weeks without doing this exercise, rededicate and advance...don't think your ability is ever 'at its peak' because...well...its not as long as you say its not.