Can you tell me about using doxycycline monohydrate for acne treatment?

Don't use alone: Never use an antibiotic as sole treatment for acne. It's a reasonably good choice, especially for a few months if you have acne on your trunk or it's otherwise fairly severe. Avoid taking it with milk and/or iron. If you have acne that's causing scarring now, consider Isotretinoin instead if it's offered to you. It's not for the faint-hearted but it works.