Can I use clindamycin phosphate topical gel to treat a boil?

Topical clindamycin is an antibiotic that is used primarily to manage severe cases of acne.
It would not be wise to use the Clindamycin without talking to your doctor first. Depending on the severity of the boil they often need to be lanced and drained first before antibiotics can start to work.
https://www.drugs.com/health-guide/boils-and-carbuncles.html