Many breeds are predisposed to cherry eye and there are some it's wiser to expect and almost considered a 'part' of the breed. You will have to see your vet, there's nothing you can do at home and without a repair constant rubbing can cause permanent damage to the eye though it isn't an emergency situation. Depending on how severe your vet may try simply putting it back (don't try it yourself :-) during the course of the initial consult and exam but that doesn't usually work for very long. There are a few repair techniques and each has their drawbacks so you will want to research that and find a vet whom does your preferred repair. The gland can be surgically removed. This is my personal preference and is usually the least expensive and once it's removed it can't happen again. The downside is a higher risk of dry eye, but that can also happen in the normal course of things and those that prefer the removal tend to do so because they have actually seen very few cases of dry eye after the gland has been removed surgically. There are a couple of procedures to tack it back down and those are more costly but it can also pop back up and you should make sure your vet has plenty of experience with the surgery.Some vet's whom prefer to leave the gland may remove it if that's what you choose if you ask nicely. :-). Just do plenty of independent research and speak to the vet to figure out what you think may be best for you and your pup. Good luck.