Suggest Treatment For Swelling And Pain After Insect Bite

2 times I have been pricked by something in my couch cushion. ( about 6-8 months apart ). I leaned over both times to get something and got pricked. Both times it looks just like a bee sting, small white circle with a red center. Both times it swells up, radiates out to about 2-3 inches, and is uncomfortable, but not painful. Could a pin or staple cause this reaction? I am diabetic. I have been using triple antibiotic ointment.