What Causes High Fever Followed By Blemishes On Leg?

Hi doctor. I'm a 31 year old female, located in Denmark. I am 170 cm tall and weigh about 90 kg I have a high fever 39-40 degrees celicius and large pink blemishes on my right leg, from knee to ankle, more near the ankle and less near the knee.
I got the very high fever in just a few hours, where I started to feel very cold, even though it is quite warm where I am. The blemishes came about 24 hours after the fever started.
I have not been traveling and I have not been around new people. Everybody I have had any real contact with in the last week or so feels just fine. I live with my boyfriend and he has no symptoms at all.