I flew about a week after I had "gotten over" a cold, or so I thought. On descent into St.Louis, I had a sinus block that felt like somebody was jabbing an ice pick through my forehead/eye ball. I eventually got it to clear, and it happened on the next leg, which is where I banged in off the trip.
I ended up going to an ENT, who diagnosed me with a massive sinus infection, did CAT scans on my head and yanked me out of work for 3 weeks. He straight up said I had no business being in a cockpit until he could get the sinus infection under control.
To be honest, I use less when that sinus block hit because the pain was so intense. Don't fly with a sinus block, it's not worth the pain/threat to safety because you could be doubled over in pain/the damage to your sinuses.