vasoline would work great, i used neasporin and put it on like once every 3-4 hours, and it made it really moist after about 12 hours if that, but i waited 24 because i too wanted to make sure it wouldnt hurt the chicken, and i would not give him anymore antiobotics, good luck! and yes a little pain will be caused by opening the eye, but the chicken will be thankfull later on after it can see out of his eye,