Hello. Thanks for writing to us at healthcaremagic You seem to have inflammatory acne. Red pimples, Pustules, Nodules etc are various types if inflammatory acne Doxycycline is an oral antibiotic with its antiinflammatory, antibacterial properties being the main mechanisms for its efficacy in inflammatory acne (red pimples, pustules, nodules etc). Oral antibiotics act faster as compared to topical creams/gels. Inflammatory acne is prone to scaring and therefore the need to control them aggressively and effectively with doxycycline. The dose of doxycycline in acne may vary from 100 mg once daily to 100 mg twice daily. It may be continued for up to 12 weeks depending on the response. Topical antibacterials like clindamycin and Topical benzoyl peroxide are also antibacterial and antiinflammatory and supplement the effect of oral doxycycline Regards