Unbeknown to me I have torn my big toe nail about a third up from the cuticle. The tear is 3/4 of the way across. I shall attempt to save the nail - if only to protect the toe beneath it. How best can I do this? Superglue has been suggested. I suppose alternative is a plaster.
I'd also go with superglue, I've used to good effect to save a broken fingernail many a time. On a toe which won't get so many knocks as a hands it should last well.
If that doesn't appeal to you then a nail salon will mend it with acrylic or similar.
Find a false finger nail that fits,file it down to toenail length and stick it on with superglue, it stays in place, supporting the damaged area and can be filed back as the nail grows out. Also looks neat and gives protection from further damage