Drugs....can they do harm if dx is wrong

I've been wondering about something and won't go back to Rheumy until March...but it occurs to me, if she's uncertain about RA- could the Plaquenil she's god me on be harming me?  I see some of the bruising that won't go away (maybe drug/maybe RA) and the swelling of the ankles/knees (again maybe drug/maybe RA) and wonder if it's in question that I even have RA- then do I need the Plaqu?  She's standing with "inflammatory arthritis" - but does that need Plaqu?  It does help me- and I do feel better than I did before, but again am I treating a condition I don't have?
I'm fortunate mine (whatever it is) isn't as bad as it could be and am grateful- but sure wish I knew what it was....and if the meds are necessary.