Typically protruding vaginal masses are caused by vaginal hyperplasia, but since Oreo was spayed young we shouldn't be seeing this condition; other causes like vaginal prolapse or vaginal tumours are possible so it is important to have your Veterinarian examine Oreo to determine a cause. (wagwalking.com)
The mass you saw may have been a small prolapse or vaginal hyperplasia which may occur during heat (which in some cases may be self limiting); regardless given her age and that she is intact, a check over by her Veterinarian would be best. (wagwalking.com)
Other problems that have been seen in this breed are ectropion, persistent pupilary membranes, retina dysphasia, kidney stones and vaginal hyperplasia. (k9puppydogs.com)