Variously called Death Day, Decision day, and a number of other less kind words, D-Day was the day that the Allies began the big push from the coast of France all the way to the heart of Germany, ending WWII.
More importantly when it comes to cystic acne, tea tree oil can be harmful to your skin when applied in high concentrations. Some individuals have reported severe skin irritation and allergic dermatitis after applying too much tea tree oil, or applying the proper dose too frequently.
If you have adult acne or rosacea, you can try a tea tree oil facial wash, diluted to about 10% concentration with water and use it to clean the eyelids (as described above) as well as the face. Tea tree oil has anti-bacterial properties that are helpful in treating rosacea and blepharitis. Try a small amount of tea tree oil facial wash on your arm as a test patch before using it on your face. Do not continue to use it if you develop skin irritation or rash.