Chagas disease, as you have probably read by now on the internet, is a parasitic disease that is caused by a biting insect. It is found in South America but, because of eradication campaigns, it is decreasing in frequency and is really mostly encountered only in rural South America in substandard housing. Therefore, if you were mostly traveling in cities or staying in hotels, the chance that this is Chagas disease is very remote.
If you are concerned about Chagas disease still, based on what kind of traveling you were doing, then there are specialized tests that can be done to rule the infection out; this is something you would need to talk to your primary care doctor
or a travel medicine doctor about.
More importantly, it does sound like you sustained an insect bite of some kind which is now likely infected, based on the fact that it has a spreading area of redness around it. I would get in to see your primary care doctor or an emergency room about this right away, as, based on what the bite looks like, you may need to take some antibiotics to help clear up the infection.