Thank you very much. I have a few moe sentences I'm not sure of.

1) I have a sunburn. I think you should rub (in/on) some ointment for burns and scolds.
2) I think you should have your leg put in plaster.
3) What do you do if you catch flu?
You lay in bed and take a paracetamol every eight hours hoping that the temperature falls (?).
4) I had to change to another type of antibiotic because the first prescribed by the doctor didn't work.
5) What remedy do you use (?) in America if a bee bites you? What is the name of the stick you put on the insect bite?
6)I had flu but I recovered after two days. (Can you say: I didn't have a temperature after only two days?)
7) I was on sick leave for a week.
8) I had indigestion (I got indigestion from eating too much). Can you say "I gorged myself on sweets?"
I think you shoud give up (?)/lay off eating sweets and go on a diet.

1 - Either "on" or "in" will work fine. The last word should be "scalds" (not "scolds").

2 - ...in a cast.

3 - "the flu" and "lie in bed" or "stay in bed"

5 - For bee and other insect stings, I usually use some kind of medicine that has antihistimine in it. Also cortisone works well.

6 - "the flu" - and yes, your alternative works fine, too.

8 - All alternatives are fine.