Hello,
Red itchy vagina can be due to a number of causes. First of all it can be due to allergic reaction or contact dermatitis to your undergarments, sanitary napkins or tampons, soaps etc.There is no change in the colour or smell of discharge in this case.
Wash the area with a mild cleanser with moisturizing properties like Cetaphil. If the symptoms still persist then you can take anti allergic medicine like Benadryl.
If the irritation persists then get it evaluated from a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
You could be allergic to latex but most likely it is just from having sex so much. Especially with a condom ladies can dry out down there and friction is created. So that's probably all it is. Next time use lube or use more lube.