smells like gas inside my vehicle hard to breathe

What is your question?

Have a 2002 Chrysler Town & Country. I live in the midwest and have to start my van a good 15 min to warm before driving. I've noticed the strong smell of gas outside & inside my vehicle. A couple times I barely could breathe. What would be the cause of this for it to happen often but not all the time? PS( I do have a small corner rear dent in bumper only on left side. ) Every now & then I had seen a darker purplish color underneath engine & half way more to left middle of van. But everything been ok when get my normal oil changes.

What makes this problem better or worse?

Colder outside possible

How long has your 2002 Chrysler Town & Country had this problem?

3-4 months