Okay so for a few weeks i have had this red rash under my arms and on the crease line of my elbows
Does it itch? If so it could be eczema. Crook of the elbow is a common site for eczema to appear. Alternatively it could just be a reaction to hot weather. If it doesnt itch just keep the areas washed and then thoroughly dried. If they itch you may need to see your doctor or have a word with your local pharmacist who may recommend a 1% steroid cream.