Mild headache. While breathing normally?

Yesterday, it was raining and I had to go out in the rain to lock the gates since rain was not stopping. There is open sewage next toy house. I wore as mask but still I could feel the droplets and drizzles on my face. I came indoors and kept trying to blow my nose to expel any water that may have gone in my nostrils. While wiping my face I pressed my nostrils for like 1-2 seconds but on releasing them, I felt my left nostril wet from inside. Can pressing nostrils briefly and releasing cause air to be sucked in and any infected water to go up far on nose or to the brain to cause am infection or can some droplets or drizzles falling in nostril go up the brain while breathing normally? My humble apologies for asking but these thoughts worry me and only way to stop them is to get the knowledge about it. I had consulted many doctors too but they say it's very rare. I sometimes feel I was so happy and careless when I hadn't read about this infection.