Advice please

I have had two retinal detachments requiring vitrectomy. I have missed close to a month of school. All of my professors will work with me to keep my A except my chemistry. I was able to accept that I would not be able to make up the labs I have missed and it would very possibly give me a B in the class, but I found out today upon returning that I would also be unable to make up a test worth 20% of my semester grade…I’m not sure what to do. I would hate to drop and take it over, because I know the material, but I also stress over my gpa. Any advice would be welcomed. Thank you.