How come my staph infected finger has not healed and it's been 2 weeks?

Several reasons: 1) Too much bacteria is present for the antibiotic to work- you may need debridement of the infected area; 2)The bacteria is now resistant to the antibiotic prescribed 3)The infection has penetrated into bone 4) It's not a staph infection- it may be something else. Regardless, you should get it re-evaluated by your prescribing doctor or else, obtain a referral to an ID specialist. Hope this helps.