When it comes to facials, one size does not fit all. While those who splurge on skin treatments regularly might tolerate a medical-grade peel, a newbie could leave the table raw. Bliss Spa, a heavenly enclave on the second floor of the W Hotel, offers a no-fail option called the “Multi-‘Face’-eted Facial’’ that empowers the aesthetician to create a customized treatment every time. A session might include a Japanese-mushroom enzyme exfoliation, a seaweed-based rubberizing mask, or the spa’s signature oxygen spray. Regardless, it’s an hour of pure bliss. “Multi-‘Face’-eted Facial,’’ $275 at Bliss Spa, W Hotel, Boston, 617-261-8747.