This is a medical emergency; take your pit bull to the vet as soon as possible. He needs urgent medical care. There is a chance that the insect that bit your pet is not venomous. The reason for that is that there the digestive enzymes present in the scorpion's sting cause a lot of pain and it depends on the scorpion's type if it has poison in its sting or not. Even if he has not been bitten by a poisonous insect, then you need to take him out to the vet too because it might not be possible to judge the nature of the bite yourself.
My Dog Got Bit By A Spider, Scorpion, Etc. I Am Not Sure. He Is Lying Down With A Steady Breathing, What Do We Need To Do?
Whether it is a sting or a bite, they are all very dangerous to dogs because poison or venom has been injected and your dog may be allergic to it. The first thing one needs to do is to put a special type of bandage for pressure immobilization on the place where the bite or sting has occurred without stopping the blood flow. A vet should be consulted if the dog is young and looks distressed.