The book "Acne Cure" states that cooling the face with ice reduces the inflammation around pores caused by built up sebum (i.e. pimples) and allows your product to enter the pores.
However, the pharmacist told me yesterday that it would close the pores.
I hate contradictory information!! You may want to check out some of the Acne Cure threads and ask someone there if they find this method is helpful or not.