Please don't worry about either. It's true that salicylic acid is not recommended during pregnancy. However, the 2% concentration you can buy over-the-counter is so mild that there shouldn't be any problem. That's why you don't need a prescription for it.
As for the Vicodin and Macrobid, I suggest you speak to the doctor who prescribed these and to your obstetrician. Drugs like these provice a benefit which, especially in the late stages of pregnancy that you're in, will I am confident clearly outweigh any risk. I'm sure you'll discover your doctors took this into direct account when they recommend them.
Best. (And good luck!)
Dr. Rockoff