Anyone know what this might be?

[LaBelleSauvage123]

A weird dark patch appeared at the base of my index finger two days ago. It doesn’t hurt and the skin feels normal to touch. Any ideas?

Did you burn it op? This happened to me after a straighter burn. It weirdly didn't hurt ( I had run under water immediately) but I noticed what looked like your pic the next day. It lasted a day or two then disappeared.

Have a look at this achenbachs syndrome.
https://www.pcds.org.uk/clinical-guidance/achenbach-syndrome

A benign condition. But if still worried see your Dr

It does look most like a burn but I don’t remember burning myself on anything. I’m not sure it’s bluish enough for Achenbach’s Syndrome comparing it to those pictures.