Local pharmacies or first-aid centers can often treat cuts, scratches or minor wounds very competently. Bathing around in salt water helps to clean and sterilize a wound. Bee and wasp stings are usually painful rather than dangerous. Calamine lotion will give relief, and ice packs will reduce the pain and swelling. There are some spiders with dangerous bites but antivenins are usually available.
Scorpion stings are notoriously painful and in Mexico can actually be fatal.
Scorpions often shelter in shoes or clothing. Certain cone shells found in Australia and the Pacific can sting dangerously or even fatally. Various fish and other sea creatures can either sting or bite dangerously, or are dangerous to eat. Again, local advice is the best suggestion. To minimize your chances of being bitten always dress your child in boots or stout shoes, socks and long trousers when walking through undergrowth where snakes may be present.