I Have A Skin Problem It Was Like Sting By

I have a skin problem it was like sting by something at the beginning, it swollen, it has a head, the head then rupture very fast and become a sore, around 0.5cm, no pus, but the sore leaking fluid non stop around 4-5 days. It heals itself and left a scar. I have this break out quite often during few months ago. what happen. I went to a specialist. doctor said it was my skin allergic. please reply my email. I can attach picture to show you. please help.