How do I deal with the therapeutic skin barrier ointment that sticks to the forehead and hands during wudu, and should I perform wudu and disregard its stickiness as long as I am treating myself with it?

Everything that prevents water from reaching the skin must be removed during ablution (Wudu'). If the aforementioned treatment can be removed without harm, then it must be removed from the parts of the body involved in Wudu' by any possible means. If its removal is not possible, despite the need for it, then it falls under a different ruling detailed in previous fatwas.