Cat has third lid showing in both eyes.

I did take the cat to the vet yesterday and he wasn't sure what was wrong with the cat but gave him antibiotics and a cream for his eyes. Today I noticed some of his hair on the side of the yard like something had pulled it out. He was out most of the night 4 nights ago which he never does. I'm thinking somethilng bit him? and he does have little bumbs on his neck and one ear.His third lids are slightly red and but his eyes are not watering. I am now waiting for the vet to call me back but in the meantime just wanted to know if anyone has any ideas what might have bitten him or what kind of treatment the vet should be giving him. Should he get a blood test? He is a bit lethargic but is eating and doing his business OK. The only animals around here are hawks, squirrels, snakes and a dog across the street that can escape but has never come into my yard. At night though I'm not sure. No other cats. Since his hair was pulled out I'm thinking it was not a snake?