The condition you are describing is consistent with balanitis which is an inflammation of the penile foreskin secondary to smegma formation and yeast or bacterial infection under the foreskin. Balanitis is more prevalent in uncircumcised men and men with poor personal hygiene. The penile discharges are accumulate under the foreskin which results in smegma formation and can lead to yeast or bacterial overgrowth.
The standard treatment for balanitis include daily retraction of the foreskin and washing the entire area with warm water and gentle soap. Remember to replace the foreskin. In addition, topical antifungal medications are the primarily line of treatment with topical antibacterial medications used as a second line.
Your prescription of Methasiazone cream is not effective in treating the most common infections associated with balanitis as it is an antiviral cream that has been used in the past to treat topical viral infections. The proper treatment for yeast-type balanitis includes miconazole or clotrimazole. The proper treatment for bacterial-type balanitis includes topical bacitraicin ointment. I would clarify with whoever wrote you the prescription or gave you the methasiazone cream what they are exactly treating for.
Perhaps you have a case of genital herpes causing cracking of your foreskin in which case, oral antivirals such as acyclovir or penciclovir are the standard of care.
Whatever the case, visiting your primary care physician for clarification of your medication, diagnosis of your condition, and possible referral to a urologist for evaluation would be warranted