dear friend, welcome to HCM.
an interesting case indeed !
usually bone tumours will not go away with antibiotics !
what meds did your doctor gave you?
disappearance and reappearance are not classic of tumours,
sarcomas (cancerous growths) are possible and do produce rapid swelling, pain , feveraetc.
, though other benign causes like a
fracture , infected
hematoma (bleed), DVT (vein system clotting) etc. can also cause these.
anyway, since an
MRI is done appropriately, it will answer most doubts.
will be glad to assist furteher if you post MRI results here.
take care and get well soon. keep posted.