Hello and thank you for using JustAnswer Health. I am sorry no one got to your question earlier.
It is possible that these are splinter hemorrhages. These may be dark maroon in the beginning but turn black over time. They can be associated with injury, small clots in the nail bed, and are sometimes associated with arthritis - which as you know may be part of the picture of Lupus. So although there is a slight possibility that it could be cancerous, it is unlikely, but you should see a dermatologist soon.
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