darkening mole is turning hard

I'm very fearful, because the past several months things have been happening and don't know what is going on. First off, in May stopped having my periods. Pregnancy test have come back negative, pap is normal and so is thyroid. Its now September and still no real bleeding, but I do have ths mole that had suddenly appeared down on the lobia think thats what its called, the flap of skin near your vagina area. Anyways it just appeared around may and now its getting bigger and hardening. Could this be what is going on and could this be cancerious. If so what kind of cancer and is this kind of cancer easy to remove?

Please frighten out of mind. My daughter just lost her father last year whose been suffering with cancer.