Yes, bubbly eye is a big indicator of a respiratory disease. Once chickens get respiratory diseases they are carriers for life. Because of this they will infect any birds that come in contact with them, including you tracking it in on your shoes or clothes.
Tylan is supposed to be injected in the breast, not the leg. I also wouldnt have even injected, I give it orally. It will take more than 1 dose. I'm not sure what you could have done to her leg.