hi, you DO want to follow up on it. Sometimes I have had docs who got no "jump" when they hit me, but were satisfied with a twitch I didn't notice. Or, you could have some reduction in reflex, but it could be that your doc has documented it and it is not progressing, in which case you really owe it to yourself to understand what exactly is different than normal, what causes it, what are the range of possible prognoses.
Or, you could have a problem that needs to be fixed. So, since this seems like someone you see regularly, I would ask next time. If you're not seeing her soon, I would ask if I could ask her a question by phone, or set up a short 'follow up' visit. Don't worry, just make sure you understand everything!
Take care,
Jane