What could make the end of my nose turn purple like a bruise? It doesn't hurt& spot is flat but the whole tip of my nose is swollen a bruise No trauma

Purpura. Hello, a non tender bruise may be due to trauma, or in the absence of any, a possible burst blood vessel due to infection or trauma that you may not have noticed. I'd try icing the tip of your nose for a few days with otc anti-inflammatory medications. If no change, check with your primary doctor for a further evaluation.