Skin Rashes Diagnosis Raised Skin Bump, Help With Diagnosis Please!?

Raised skin bump, help with diagnosis please!? - skin rashes diagnosis

about 1 week I had a piece that rises only in seconds, Scratch and Red seems to come. When I press down on bump on the skin, as if filled with air or water. The rash, itching, but it's never just itches to scratch or touch it. Please help diagnose