I think that these symptoms are very worrying, and I think that you need to seek immediate medical attention. You should see either your primary care doctor
or go back to the emergency room for evaluation.
The fact that you are having swelling in the region of your elbow is concerning. If this is in fact a lymph node, persistent pain and swelling could indicate that you developed an infection in the arm when you cut yourself. Other symptoms that might indicate an infection would include redness or warmth of the skin or fever.
The bruised area that you have above your elbow also needs to be evaluated. Sometimes, large bruises or contusions of muscle tissue can result in significant pain and swelling from blood that has leaked into the tissue. Without being able to look at the arm, I still wonder if the swelling above your elbow might be from the contusion
and not a lymph node.
Your doctor will be able to examine the arm closely and help figure out what is going on. If you have any evidence of an infection or abscess
, this will need to be treated with antibiotics. If this is just a large contusion, it should improve slowly, but you may need a better pain and anti inflammatory regimen from your doctor.