How does one tell the difference between a bug bite and a tick bite?

Ever since I arrived to South Korea, I have gotten multiple bites on my arm, legs, face, etc. Whenever I itch them, they turn red and form a red circle on my skin. They are bumpy, as well. What is this? I have several of these on my arm. Some are less bumpy and some are very big. Is this Lyme Disease or a lot of bugs biting me?