Hello,
For some perfumes the expiry date is mentioned. You can call up their customer care and inquire about the shelf life. However if it's discolored, or if you smell
the same as it did when you bought it, then you should start using new ones.
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.