I'm sorry that happened to your co-worker. Sadly, that's all too common, the gossiping that is. The thread in this section of the forum discussing territorial aggressions by women to women is spot on. I can only imagine what that might be like for your coworker. It's no secret where I live in my place of employment, and where I live has quite the reputation as a hubbub of "distribution" (of drugs not exaggerating) and also the landing spot of those discarded for addictions from surrounding communities (hence the large homeless population. That said what most neglect to recognise is that it's a quiet but large spiritual center(meaning more churches than one can count and loads of evangelicals and traditionals). So there's a telltale difference here between both sides of that path. Not that gossiping nitpicky critical masses care.
In the meantime, not looking exhausted has a huge effect in the workplace.
I hear you about wanting to limit the time and attention to it. It's a matter of finding what works best for you and getting it so routine that it's not taking more than but a few minutes of your time. I multitask between layers of skin care. Wash face/tone...grab clothes etc...I space it out.