This trial is testing tranexamic acid, a medication that can lighten dark patches on the skin, on patients with lichen planus pigmentosus (LPP) and erythema dyschromicum perstans (EDP). These patients have not found consistent relief with other treatments. Tranexamic acid works by reducing inflammation and blocking processes that cause the skin to darken. It is increasingly recognized for its utility in treating various skin conditions, including melasma and post-inflammatory hyperpigmentation.