To be worried about this on my mums arm?

[Luckkk]

What could it be? Just came up some time but my mums just noticed it

It’s quite hard to tell but is it just some blood under the skin?

Looks like a blood bruise type thing to me, like when you trap or pinch your skin in something and the blood wells up under the skin. Take photo and send it to e-consult if you’re worried though.

I'd just think it's were a sleeve has rubbed or pinched my skin. It looks like a flat blood blister. We mark easier as we age.