Please help bites!

I wanted to know if anyone can give me advice on these bites. I am very confused and I sleep in the same bed as my baby sister and she has nothing. They only show up on my ankles and feet and I heard fleas bite there but I have no idea. I’m allergic to dogs and I actually have one so maybe but it looks more like a bite. I wash my sheets every single week and I’ve never seen bugs in my bed and my mattress is new. I just hate it. It itches so bad. They have been on my arm only once.

This is my leg and you can see the scars from me itching it so badly.