I am having the same issue- red cracked nose, going through a box of tissues a day. My doctor told me I could use sudafed. I bought a low dosage and was hoping to not need it but I had a break down last night. After being up from 2-5 AM and not being able to breathe (really bad post nasal drip)- tried steam, tried saline, vicks plug ins- nothing worked and I broke down and took one pill. It helped enough to let me sleep.
You should call your doctor though before you take anything that isn't a "natural method". Your doctor knows your pre exisiting conditions and wouldn't tell you take something that is going to injure the baby.