This analysis went back to the two pivotal oxymetazoline trials, covering 885 people, and looked only at what happened on day one. More people improved by at least one grade with oxymetazoline than with the placebo cream at every point measured, starting at hour 1. It shows the cream begins working the day you start it. It does not tell you how much redness any one person loses.
Tanghetti EA, Dover JS, Goldberg DJ, et al. Clinically relevant reduction in persistent facial erythema of rosacea on the first day of treatment with oxymetazoline cream 1.0%. J Drugs Dermatol. 2018;17(6):621-626.