I have some difficulty in understanding the metaphor or implication of "a life impervious to skincare routine". I could sense that the speaker is speaking about the old woman in an approving tone, but what does she actually mean? That the woman is so strong, tough, mentally and physically, and experienced, so that she did not care about the facial beauty? Why use "skincare routines" here? My guess is that "she does not use skincare because she doesn't care"?? Could anyone please help me understand, or rephrase it in a straightforward way?
In the context: 'I' was the carer of Will, a quadriplegic in wheelchair, and we were at a wedding reception, and the woman is also a guest.
Here is the sentence, and all the related context:
The elderly woman on his right turned out to be a former MP who had campaigned on the rights of the disabled, and she was one of the few people I had seen talk to Will without the slightest discomfort. When she briefly got up to leave the table, he muttered that she had once climbed Kilimanjaro. ‘I love old birds like that,’ he said. ‘I could just picture her with a mule and a pack of sandwiches. Tough as old boots.’………
………… At one point, when I started to feel properly awkward, I felt Will’s arm slide off the chair beside me, and his hand landed on my arm. I glanced up and he winked at me. I took his hand and squeezed it, grateful that he could see it. And then he moved his chair back six inches, and brought me into the conversation with Mary Rawlinson.
‘So Will tells me you’re in charge of him,’ she said. She had piercing blue eyes, and wrinkles that told of a life impervious to skincare routines.
‘I try,’ I said, glancing at him.
‘And have you always worked in this field?’
‘No. I used to . . . work in a cafe.’ I’m not sure I would have told anybody else at this wedding that fact, but Mary Rawlinson nodded approvingly.
Me Before You by Jojo Moyes