Someone posted a graph showing how propecia continued to effect DHT levels even after stopping taking it. I wish I could find the post now, it basically seemed to have some effect on DHT for about a week after stopping, but only really having a significant effect on DHT for the first 3 or so days.
Thats the effect on DHT but it takes much longer for the benefits from taking finasteride to be lossed once stopped, something in the region of 6 months to a year for your scalp to revert back to how it would been if you hadn't ever taken the drug if I remember correctly. At any rate a few hairs lost is nothing to lose sleep over at this stage
I've a related question to this, I've always wondered how long I would have to stay off finasteride if my g/friend and I wanted to try for a baby, any ideas?