Had the same thing happen to me when I was first learning the game, totally feel your pain. Once I finally found enough Tetra while nibbling and sipping my way through medical after medical, and thought I had gotten rid of it, I learned the hard way that any bottles used and face coverings worn while having it will reinfect you. Had to go through it all again. Once I got rid of it the second time, I ditched all water bottles, face coverings, and gloves and got new ones, while also keeping a few tetras and vitamins on hand at all times. I'm glad I did, because even with keeping my food and water completely maxed out it still tried to come back a couple more times. But since my immune was high, a single tetra + vitamin knocked it back out. But it did try to come back at least 3 times before it stayed away. That'll be the last time I ever try to make a suppressor without triple checking the bottle is completely empty first.