I went into a grassy abandoned backyard to grab a baseball, I'm pretty sure i wore flipflops. That very night i had a small bump on my foot. Looked like a mosquito bite and more bumps popped up around it until they all merged to be a giant lump the size of my hand and then it just went away. Couple hours later it reappeared but near my cavs, one small bump, more popped up near it and then became a giant lump. It went away and slowly came back every couple hours, top my hip went away, abdomin. Chest, neck, until it reached the top of my head and then it just disappeared. Any idea what this might have been?