Talk to Rheumatologist on Pustule On Foot

I got a pustule on my foot 4-5 days back. I used a belladona plaster on it but it didn't pop. 2days back, I walked during which the strap of my shoe irritated it repetitvely and now my foot is like in picture. A small red streak around 2inches is visible around the wound and edema. It is tender to touch but is at normal temperature like the other body parts (not hot ) . Painless when at rest but painful when i stand for more than a minute or walk. No other signs/symptom. Kindly guide what to do.

P.s. i am a known case of dermatitis since childhood and get flareups every couple of months . Thankyou in advance for your help !