had a big black head right in the middle of my nose. I've just got it out really easily, but now i have an big open pore. What should i do to prevent dirt from getting in there and clogged again (so it doesn't get bigger). Should i avoid moisturizing, and products there general? Anything i can do to shrink pores? I don't have acne otherwise, just this one annoying open pore (previously blackhead).