My wife is 63 and is healthy. Every once in a while she gets a small slice in the crease on her labia minora on the left side which is painful when she urinates. We put diaper ointment on it and it heals but comes back from time to time. Today it appeared on the right side and is a much longer split than usual. What would cause this? We know it has nothing to do with trauma of any sort and it was not there yesterday.