Lamium and Stinging Nettle are not related. Lamium,Dead Nettle, got it's name only because it looks like nettle but without the "sting".
I am unsure if it is edible. All I know is that it is said to have healing properties and be a bit astringent (like cranberries and raspberries). I believe it is edible but cannot say for absolute certainty or what amounts would be safe.
For "fun" information about Lamium (also called Archangel)
-the plant is ruled by Venus. Therefore a "woman's" herb
-In olden days it was used for:
-stopping hardness of the spleen
-The white flowers were used to "stay the whites, and the red flowers used to "stay the reds" in women. (Don't ask I have no idea-this is an old text I'm using here)
-It makes the heart merry
-drives away melancholy
-quickens the spirit
-is good against the quartan agues
-"stauncheth bleeding of the mouth and nose if it be stamped and applied to the nape of the neck"
-"The herb bruised with salt and vinegar and hog's-grease laid upon a hard tumour or swelling, or that vulgarly called the king's evil, do help to dissolve or discuss them. In like manner applied, it doth much allay the pains and give ease to the gout, sciatica and other pains of the joints and sinews, It is also very effectual to heal green wounds and old ulcers. It draweth forth splinters and is very good against bruises and burnings. The yellow Archangel is most commended for old, filthy, corrupt sores and ulcers, although they be hollow, and to dissolve tumours."
More modern uses are to drink 2oz of a tea of the dried flowers (1oz flowers to 1 pint boiling water steeped for 20 minutes then strained) once a day. This is said to;
-relieve menstrual problems and leucorrhoea in women
-prostatitis in men
-for catarrhal conditions requiring liver stimulation.
Please do not use this "medical" info yourself.. This is for fun info only and I do not recommend anyone try to use any of these home remedies without consulting both a medical doctor and a psychiatrist.