Blue Light healing is extremely versatile. According to Mom 2, healing is one of the ring's core functions, and a major strength of The Blue Light of Hope. The ring uses available biological and medical data, as well as the relevant hopes of the target and others nearby, to identify problems, sites and sources of pain, sites of dysfunction, and even future problems that lie dormant.
Then, fueled by the combined hopes of the wielder, the targets, and those nearby, it acts.
Filaments too small to be seen with the naked eye enter bloodstreams and shoot through veins, rapidly deconstructing harmful microbes, bacteria, and viruses and rebuilding them into vitamins, simple sugars, or other helpful resources, as needed. The molecular memories of faulty immune systems are systemically rewritten, drawing on available examples of healthy ones and the ring's formidable modeling capabilities to ensure safety. Structural damage of all kinds is repaired; plaque removed from arteries, toxins cleansed, chemical imbalances restored. Wear and tear on organs is identified and patched up; broken bones are made whole.
Cancerous cells are sought out and broken down, the transcription errors that caused their unbound replication identified and repaired. Tumors are painlessly disassembled, the excess mass seeming to disappear in the blink of an eye.
Those wounded by gun or knife are reasonably straightforward to treat; damaged organs and veins are rebuilt by tiny strands of blue light, followed by layers of skin. Those shot are scanned for traces of lead or other foreign contaminants to be removed. A soothing blue light passes over burned areas, restoring the flesh as though it'd never been touched.
(There are limits to what can be done for brains; root causes can be identified and addressed and some kinds of damage can be repaired, but the ring can't restore memories that are no longer encoded in neurons. Even with this kind of power, some things can't be fixed.)
The entire process is quick, painless, and leaves the patients filled with a warm sense of hope; a feeling that All will be well, whispered into their hearts.