I took my mom to the hospital for a swollen left titte the dr said it might be a mass she gave her some clindamycin hcl 300 mg she is a diabetic and have heart failure should she take this?

localized breast swelling/redness/pain is likely an infection and clindamycin is a good/effective antibiotic for this condition, especially in a diabetic person. If not better in a week or so, she should be evaluated for possible condition called "inflammatory breast disease" which is a rare form of breast cancer which can mimic an infection. Good luck

This is not the question you want to ask someone who has never talked to or examined your mother. Listen to one who has.