kitten won't eat when other cat is near

I have a 7 month old, very talkative kitten that we brought home when she was 8 wks old. We also have a 7 year old cat who didn't appreciate it too much. The kitten began following the cat around and trying to nurse from her and our cat was having none of that so she quit but then became very aggressive towards our cat. The kitten would literally just beat the crap out of the cat and the cat would take it. We started to wish the older cat would just beat the kitten up once and be done with it!
Then 2 months ago I was hospitalised for several weeks and off work. My husband fed them at the same time I did and tried to make everything on time. When I got home, however, I noticed that the cat had finally 'manned up' and beat the kitten up. She was unable to eat for several days because her mouth swelled up so much. I hand-fed her wet food and the swelling healed. Now she will NOT eat if the older cat is around. I'm not sure if this was the incident that did it (because they still beat the snot out of each other and then bathe each other like best of friends) but if the cat comes into the room the kitten will come sit by me. When I give them treats I have to stand right over the kitten or she'll shy away and run. How can I get them to eat together again?