it looks like you had frictional injury
that got worse due to secondary infection and the white little spots may be pustules, and that might be the reason you are getting fever
Apply warm compresses (cloth soaked in warm water, not too hot) over the area
and take a course of oral antibiotics
500 mg twice a day for 5 days or amoxyclav once a day.
for the pain.
Another explanation is bartholinitis, infection of a gland located in vagina, in which case you must consider consulting a gynecologist.
Thank you, hope I helped. Feel free to follow up in case of doubt.