Atrophy can occur from a hormonal imbalance, following a hysterectomy or perimenopause/menopause ; the latter of the two can bring about vaginal atrophy, although it can be avoided and/or reversed.
Another thing that could be happening is overstimulation, in which case, give pause to recover.

So, let's see if I understand this, the hood is swollen, but the clitorus retreated, not enlarged?