We say nothing after sneeze. We don't have this kind of culture. Although when I was a child, adults would say "bǎi suì" when babies sneezed for the first time, and say "qiān suì" for the second time.
"bǎi suì" means "one hundred years old"
"qiān suì" means "one thousand years old"
I guess it was kind of bless on babies. Sneeze usually says that you don't feel well or get a cold, so adults said that to babies to pray for their health, hope they can live longer, longer than 100 year-old and even 1000 year-old. Although it's impossible.
I don't think people still do it nowadays. People in some rural areas may still do it, I'm not sure.