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.
Used as an ingredient in acne washes, pads, cleansers, and astringents, tea tree oil is said to have anti-inflammatory and antiseptic properties. 1  The oil contains a variety of constituents (such as alpha-terpineol), with terpinen-4-ol being the purported active ingredient.