This is 'Self Portrait' (1899) by the British artist Hillary Coddington Lewis (1871-1936). She doesn't have a Wikipedia entry and I haven't found any information about her apart from the fact that this painting and another two of hers are in the Blackburn Museum. This led me to think she was probably from Lancashire, and a bit of poking around revealed that she was the wife of a Blackburn textile magnate, Thomas Boys Lewis, who was a collector of Japanese prints and donated to Blackburn the Lewis Textile Museum.
When a painting is labelled Self Portrait, I always try to work out how exactly the artist managed to produce the image. I suppose the most common way would be to paint it while looking in the mirror. This one can't have been done that way so presumably she worked from memory?