get even worse with/by each sting.

[yi-ing]

Are these bold words correct here?

Now, I have to be extremely careful not to get/be stung again, because it could even be fatal. Such allergic reactions can get even worse with/by each sting.

 

[bhaisahab]

You can use either 'get' or 'be', 'even' is fine. Use 'with each sting'.