Skin discolouration after abcess (dog)

[Lotobear]

My Lakeland Terrier had a very angry abcess on her side which I think resulted from an infection after she removed a tick and left the head in.

Vet had her on antibiotics but it eventually had to be drained and a load of pus came out. It's now healed and settled down but a large brown pigmentation has developed over the site and there is no sign of fur re growth to the immediate area (it's re growing where she was shaved by the vet). She's a red terrier so her skin is pink which makes this strange pigmentation all the more obvious.

I'm not at all concerned about the cosmetics of it just curious as to why it has gone this way and whether it will revert in time. There's no tenderness and the site has otherwise healed beautifully and she's not aware of anything.

Interested for obvservations/comments?

[Lotobear]

Now with photo,

It's just occurred to me she spent last week with the inlaws in Nottingham (where I understand the weather was sunny) when we were away skiing and that is when the dark patch appeared. She spent a lot of time lying in the garden so I'm thinking her exposed pink skin has probably just got a suntan!