Old folks in my country use this method :
-Get one big onion
-peel it and then cut it on very fine pieces
- put it around the swelling part ,then wrap it with plastic bag in order to prevent the juice to leak
- wrap scarf or piece of cloth around lastly.
Then leave it overnight .
The thing does smell pretty much therefore better if you apply it before you go to sleep and then at the morning wash it away in case swelling is still present repeat in evening .
My grandmother used that on me from kid and i still use it .
It helped me to stop the swelling of broken thumb till doctors get involved .
Hope you will get better soon .Good luck and best wishes .