Hello viVian,
First of all, I will also have to say that the eyedropper trick is pretty ingenious
I'm sure someone with more knowledge on the matter will get to your question soon, but in the meantime, just to share my own experience (and from what I've gathered hanging around these forums) I learned that just 1 or 2 (or 4) doses will not do it. It has to be continuous work. I fed my target my blood for a whole month before things got really better, and this was done alongside working a honey jar, laying tricks with oils and powders, and having a love drawing and love uncrossing ritual done by a rootworker.
I agree with what candlijojo said, in that the magic is working inside of him. All the effects are still internal and he has to deal with the emotions by himself. Perhaps eventually when he is more comfortable with those feelings he will then start reaching out and the effects will be more visible on the outside.
Just keep feeding your target whenever you can, and trust that eventually you will get what you want.
In my situation, around a month ago my target didn't even want to be around me at all (She was really going through some effort to avoid me, and this isn't an easy feat considering we live together! There was even a time when we happened to be at the same place outside at the same time and she was hiding behind a food stall in order to hide from me.) And now, after a month of everyday doses in coffee and drinking water, we are talking and laughing and she has been asking me out to dinner on the weekends.