a. a girl has a burn on her arm.

⇒ I will use cold water to ease the pain and then take her to the nearest clinic/ hospital if necessary.

b. a girl has a nose bleed

⇒ I will leave her lying flat and stuff her nose with cotton-wool to stop the bleeding.

c. a boy has a bad cut on his leg

⇒ I will wash the cut with bactericide. Then I'll bandage the cut to stanch it.

a boy has a bee sting

⇒ I will apply lime to the area around the sting to stop the sting from being swollen.