It is commonly called Cherry eye. Nothing at home is going to help. They can try steroid drops, but generally surgery to tack it in is needed. You don't want to risk it becoming infected or injured. Having personally seen surgery done wrong, I strongly suggest you find a vet who is experienced in the practice.
If it's cherry eye, you can actually gently push it back in place by using your thumb. Not by touching the eye or the red part, but by massaging gently below the eye. This should get it back in place. If it keeps returning quickly, then yes, surgery is the only way to go. But some dogs only get it a few times their whole lives, and some get it a couple of times a year. Then it's better to avoid surgery, especially on an old dog.
Thank you for your help. I took her to the vet. They prescribed eye drops to see if it would help. They stained her eye. No scatches. They eye is slightly recessed. I will try the massage as you suggest. I really don't want her to have surgery. But I don't want her to be in pain either. Hoping the massage helps. Thank you.