Answer:
Dear Anon,
You say it happens when you are aroused. What you are experiencing is normal. When a woman is sexually aroused, the first thing a body does is increase blood flow to the genitals. In a woman, the increased blood flow causes not only lubrication, the first sign that a woman is aroused, but also a swelling and deepening of color to her clitoris and inner lips. Colors change from pinks to reds, and from reds to wine or burgundy. (Similarly, the male erection is the result of increased blood flow to the penis.) After a woman orgasms, or when she is no longer aroused, her regular color returns, since flow of blood leaves the vulva and returns to the rest of the body.
If you have no other symptoms then discoloration, I shouldn’t worry to much. If you do have other symptoms next to discoloration, please message me about them (: