IME decongestants can cause dry, hard stools, and that can make hems worse. If you need an decongestant, try adding some Metamucil or psyllium fiber & LOTS of water. Or, a little mineral oil.
If you are taking an antibiotic that is causing diarrhea, that (and frequent wiping) can also aggravate hems. Add a probiotic (like yogurt w/active cultures, or a supplement), and use a warm, damp tissue wad to wipe. That's less irritating than dry, scratchy TP. Some people swear by tissue wipes, but I find the chemicals in the wipes irritate my hems.
With any luck, if you need to take both a decongestant & an antibiotic, they would cancel each other out
Best wishes.