cellulitis feet

[michaelsss]

My right foot got  burning itching and hot on Monday's night. I thought it's athlete's foot and got the athlete foot cream in Walgreen on Tuesday, but didn't help. It got swollen and hurt on Thursday night and I went to urgent care on Friday's morning. The doctor prescribed me Clindamycin,but seems didn't help at all and the blister between toes got bigger(Only one blister). I followed up with him Today(Saturday) and he suggested me to go to ER. So I went to ER and the doctor prescribed Keflex and extracted the blister. Suggested to follow up with my doctor in 1 or 2 days. I don't think I can make an appointment within a week.  They didn't do any lab test. Are there any lab tests to to verify it's cellulitis feet? I'm starting to get worried because seems the medicines don't help at all.