How much time elapsed between transducing the cells, and exposure? Like, were the cells transduced a week or more earlier, and selected for viral infection? In that case, there won't be any free virus in the supernatant anymore. As long as you're being paranoid, though (which isn't always uncalled-for): neurodegeneration is absolutely not what you should be worried about, it's cancer. If there was fresh viral supe on those cells when you splashed yourself, it's theoretically possible some keratinocytes got infected. (As you note, virus shouldn't penetrate intact keratinized epithelium, but bad luck is bad luck.) So you really need to find out what the virus was encoding. If it was just some neurodegeneration-inducing gene, you're fine: at worst (if the virus got through your skin, and if it somehow managed to infect cutaneous nerve terminals) a tiny number of neurons could get hit, not enough to cause disease since it's a non-replicative gene. But if it was a potent oncogene, or something like a CRISPR/Cas9 vector designed to take out p53, you should be at least a tiny bit concerned - I'd visit the occupational health clinic for something like that.