Thanks for writing in.
It seems that your perineal muscles have gone into a spasm which is preventing you from a putting a tampon in. This can occur due to an infection in the urinary bladder
or a condition called vulvodynia.
However, a perineal muscle spasm
and spotting can be suggestive of a pelvic inflammatory disease
, particularly if you are sexually active.
Meanwhile, a topical anesthetic
like lignocaine applied locally, can help reduce the spasm and relieve some of your symptoms.
I would suggest you see your treating physician as soon as possible.
Hope this helps.