If you have blackheads, then you also have enlarged pores. There is little that can be done to tighten pores without going to an actual dermatologist I know, I have pores a truck could drive through The best thing to do with acne & blackheads is to change your diet.
A low glycemic diet has been shown to decrease breakouts
I have found it also help reduce sebum (the black stuff in your blackheads). Other things to reduce sebum are found at the link. Personally I think you’ll need one of these along with a good salicylic acid program like this one
Best wishes to you on clearing your skin!