All of us bite/cut our tongue at one time or another, sometimes while we are eating and at other times by accident. Maybe you have scraped your tongue against a rough surface. Also, if you have an impacted tooth, the tongue may rub against the edge of it and become bruised. Usually a bitten / bruised tongue is not extremely serious. However, if you have severe and uncontrollable bleeding, you should get emergency treatment. After the pain of having bitten your tongue, the pain usually is discontinued after a couple minutes.
If the bruise on the tongue is not too serious, you can try the following:
1) Apply toothpaste onto the bruised part of the tongue. The mint releases a cooling sensation onto the stinging area.
2) Gargle with salt and water. This helps to maintain the salinity of the tongue and heal the wound. Sometimes you may only need to gargle with lukewarm water.
3) You may also grab a piece of ice and place it on the affected part of the tongue. The ice's coolness will diffuse the pain. Also, the ice cold feeling helps the exposed blood vessels to heal faster, thus preventing further bleeding.
4) Applying aloe vera juice against the bruise will help treat the bruised tongue. Sometimes aloe vera comes in a gel form that makes applying it easier.
5) Gargling cold water and holding the water in your mouth helps some people get rid of the pain completely.
If you do this, be careful that the water is not so cold that the blood vessels in the mouth become numb. Good luck!