A friend of mine aged 78 has a very swollen leg, (it's paralysed due to a stroke) it's full of fluid and if I touch it my finger leaves an imprint for a short time. It's been getting worse every time I see her (once a week) I noticed a mark which she says is nothing and it's where she knocked it. It's weeping the fluid from her leg. Could this be the start of an ulcer?