I am not sure what test you had but 18% is probably a cell count as ESR CRP WCC are usual tests to see if there is ongoing inflammation and none of the above tests are reported as percentage.
With your background history, and fever
with swollen joints and paresthesia
, you need to get in touch with your Rheumatologist
as soon as possible.
Joint aspiration for pus c/s and examination for crystals, plus increase in pain relief medications and/or immunosuppression
will then need to be decided as per the results.
Wishing you a speedy recovery.