Well, I can't give you the level of advice that the other posters have, since I've always been a low-level/"just for fun" user. I mean, my gig has never really required me to know Perl, even though I've accomplished much only because I could whip together a script that got the job done. (There's a reason Perl has been called the "duct tape of the Internet"!)

But, I can say this, in regards to being away from Perl for a long time and coming back: The best way, for me, has always been to solve a problem. In fact, that was how I came to learn Perl in the first place. I had a problem to solve and Perl was the the wrench I chose to pound the nail. Seriously, find some small project that you want to accomplish, either at work or for yourself, then, discarding as many of your old ideas about Perl, try to solve it.
And, of course, keep coming back to PerlMonks! Sometimes, I just learn stuff by reading and voting!

Good luck!