My gf's new tongue piercing started to bleed profusely. do you know what causes this? she had alto of blood clots also in it.

Remove the piercing: The bleeding was caused by too much use prior to the piercing becoming fully healed. Remove the piercing and allow the hole to close if the bleeding continues or if she is willing to lose the piercing. If she would like to keep the piercing, apply pressure, swish and spit with salt water and try not to use the tounge. Drink fluids and do not eat rough foods.

Hemorrhage?: The tongue contains large blood vessels. If one of those vessels is perforated by the piercing it can lead to hemorrhage. In some cases that requires that the peforation in the blood vessel be surgically closed.