Hello,
I saw that no one has answered your post yet, so I hope I can help you.
Its possible that the swollen face can be from the tick. Ticks and other blood sucking buggers can carry a whole array of bacterias that can infect their host. Are you sure it was a tick and not some sort of scab? Maybe your hen got pecked- was it at the top of the head or above the eye? If so, it could be that she got pecked as this is where a lot of hens aim when they mean business!
I'm not at all an expert on chicken health, but I read a lot up on it and my concerns are is that it looks like is something called infectious coryza. However, I find it curious that her waddle is swollen also- Because of that, I'm doubtful, thinking it could just be an infection from either a tick bite or maybe from being pecked.
It would be helpful to post a few more pictures at other angles. Also, there is a guide/write up on the top of the page of the emergency/diseases/injuries and cures page labeled "Have an emergency/disease? Please read first"... In that you will find a questionnaire for you to fill out and post that will help others help you.
Some questions...
Is the chicken having any breathing difficulties? Any rattle-like noises coming from its beak? Any discharge coming out from the nostrils?
If this is just bacteria from an injury or infected tick bite, then antibiotics would be your best bet.
I'm not sure of the treatment for infectious coryza, but I think it is something you would need to treat as soon as possible as it is 'infectious'. I think ... if I remember correctly... that Duramyacin 10 in your flock's water would help that, but I'm not sure...
I apologize for not being very helpful.... Right now, I am away from all my books and things to help you better because we are remodeling the room and there is no way to get to things, so please be sure and do a web search on those terms to check and see if your chicken as similar symptoms. Those webpages should also help you with treatments if you so assess what it is. I hope someone else can chime in and share their thoughts as well.
For now, I would separate the hen from the flock and watch for more hens having the same problem. I'd also get some antibiotics for your hen. Preferably something that is water soluble.
Let us know what happens!