Hello and welcome to HCM
As you have described that symptoms of itchiness and swelling were more after using tampons thus it is obvious that they could be due to them.
This may be an allergic response
to some allergen in the tampon.
Please discontinue its use and observe for a few days.
You can take an antihistaminic as well.
If the symptoms are over after discontinuing the use of the tampons then the cause is very obvious.
If it does not then you need to consult your gynaecologist.
Also as a precaution avoid sexual contact for the time the symptoms are not relieved as it may aggravate the symptoms.
Thanks and take care
Dr Shailja P Wahal