What Causes Redness And Swelling At The Tip Of The Nose?

5 days ago i woke up in the morning with a red-tip nose. during these 5 days it got swollen, more red, rough with rush-like ruptures fom underneath the skin. Today, swelling reduced, redness reduced, however the central part of the affected area has become dark with a well marked outline. pl tell me what is it? i'm 58, male, 5.5ft tall, asian, 53 stones in weight, boarderline t2dm. no other health problem. i'am currently in a hot country (bangladesh)and the night before the start of the episode was very hot.