Welcome to HCM
We understand your concerns
I went through your problem description. I suggest you not to worry too much. The sweating between legs are very common and odor is also pretty common. Hygiene and cleanliness plays an important role in those areas.
Obesity is just one cause of body odor
. There are so many other causes. Keep yourself clean and dry. Use some moisturizing mild soap to keep the area clean. Taking bath with warm water (boiled with a bunch of neem leaves in it) could give you good result.
Hope this clears your doubts. Available for further clarifications.