What Causes Swelling And Stiffness In The Finger Joints Post Injury?

Question : Sep 7
Got Splinter in finger (at joint of index) from a wooden skewer while working with raw meat. Splinter pulled out.

Sep 10
Finger swollen and infected with blister. Started CLINDAMYCIN 300mg 3 times daily at advice of doctor. Took for 4 days.

Sep 13
Swelling extended to whole hand. Got incision to drain out pus and started Augmentin 1000mg for 6 days

Sep 14
Swelling reduced

Sep 23
Minor swelling localized in finger only but arm from fingers to elbow is weak with pain in arm felt mostly at night. Family doctor prescribed CIPRO for 10 days. Suspected that infection remains present.

Sep 27
Specialist (Plastic surgeon) does not suspect cellulitis. Says probably inflammation from initial infection. Prescribed 7 days of clindamycin 300mg 4 times a day just in case in addition to the cipro. Weakness in arm remains. He suggested to gently exercise it.

Sep 30
Pain from hand to elbow remains, mostly at joints (fingers, wrist, elbow). I suspected it was tendonitis due to initial infection. Went back to doctor and he said he doesn't think it's tendonitis. He's sending me to hospital to get galium scan and bone scan to rule out septic arthritis or bone issue.

Oct 18.
Bone Scan and Galium Scan turned out negative for septic arthritis or other problem. Doctor said it is only inflammation from injury and to massage finger constantly with hot compress.

Oct 31
Initial injury has been almost 2 months old and finger has healed from the actual trauma but finger remains swollen and stiff. Cannot do normal activity on left hand as it is weaker and activity usually leads to pain in my whole left hand and wrist after excessive movement.

I cannot believe that a simple tiny splinter led to this outcome. What can be wrong? I'm not convinced that it's an underlying inflammation only. What is your opinion? I'm thinking that I have damaged tissue in my finger joint and this is causing my lack of mobility and slight pain.