What medications can be used to treat cold sores?

Not much at home. Keep it clean. Treatment in an office can burn these things away, but only in really bad situations.
Antivirals. Antivirals such as acyclovir, valacyclovir, famvir, (famciclovir) and gancyclovir are the most common. My sine as an otc as well as abreeva work as well.
Antivirals. With the notion by some providers that "cold sores" could be of viral origin (especially herpes a), anti-viral ointments or creams, steroid ointments or creams, or systemic antiviral medication is frequently used. Dr. J.