Hey I Have A Lump Around My Bottom Or Lower

Hey I have a lump around my bottom or lower back and it's a pinky colour and its warm to touch, painful to touch or lay on my back or sitting can even be painful. I take Advil and it feels better and I use ice which makes the swelling go down but as soon as they wear off I'm back to total pain. I have a flight to Seoul tomorrow and I also wanted to know if it was safe to fly.