I am not sure of the exact action of the scorpion venom but I would use plantain externally and internally to help pull the toxins out at the very least. DO NOT apply heat to the plantain.
From Wikipedia
Sting and venom
All known scorpion species possess venom and use it primarily to kill or paralyze their prey so that it can be eaten. In general, it is fast-acting, allowing for effective prey capture. It is also used as a defense against predators. The venom is a mixture of compounds (neurotoxins, enzyme inhibitors, etc.) each not only causing a different effect but possibly also targeting a specific animal. Each compound is made and stored in a pair of glandular sacs and is released in a quantity regulated by the scorpion itself. Of the 1,000+ known species of scorpion, only 25 have venom that is deadly to humans; most of those belong to the family Buthidae (including Leiurus quinquestriatus, Hottentotta, Centruroides and Androctonus).[8][35]
First aid
First aid for scorpion stings is generally symptomatic. It includes strong analgesia, either systemic (opiates or paracetamol) or locally applied (such as a cold compress). Hypertensive crises are treated with anxiolytics and vasodilators.[36]