What Causes Large Bruises With Raised White Patches Below Left Hip And Armpit

I'm 17, 5 foot 4 and weigh 8 stone. I've never had any major health issues. Recently I've noticed a large bruised area just below my left hip, which surrounds a mole. I have also developed a few rust-coloured bruises around my left armpit. These have both been accompanied by a burning rash that leaves large, thick areas of raised, white patches on my skin. I am planning on visiting the doctor, but not until later this week. Any idea as to what this is?