Hello, On Thursday Morning I Woke Up With This Bump

hello, on Thursday morning I woke up with this bump red on my foot it looks like this red rash with a hole bunch of bumps inside went to doc on Monday they don't know what it is next morning at school I had this little white dot that was itchy now went everywhere it start hurting like if someone was giving me a shock or even little needles. I am allergic to many things so have to be careful but can it be the thing on my foot? should I go back to docs? should I worry?