Weak Fingers

I recently began teaching piano. I love it. I love teaching and seeing my students (most of which are actually excited about it) learn and progress. But one of the things I love most about it is that it's motivating me to get my butt, or rather fingers, back in shape! For all too long I've gone without challenging myself, just playing for fun, and only practicing select songs for primary. Lately I've been pushing myself to do exercises and practice songs that will challenge my technique. Man do I have weak fingers! I just spent 10-15 or so minutes doing scales (the first time I've done scales with a metronome in probably more than a year, I know it's bad) and man my fingers are killing me right now. In fact I'm not quite sure why I decided to type this right now because it's not helping, so I'm done...