Sting is usually a verb. Its past tense and -ed participle is stung.
If a creature such as a bee, wasp, or scorpion stings you, it pricks your skin and pushes poison into your body.
Don't say that a mosquito or ant 'stings' you. You say that it bites you. The past tense and -ed participle of bite are bit and bitten.
You also say that a snake bites you.