Thank you for your question. My name is***** and I will do my best to provide a useful input.
From your photographs and history your rash could be one of three things -
1. A fungal or yeast infection - these are caused by heat and humidity and are extremely common in the areas mentioned.
2.An allergic reaction to something used in those areas (e.g. razor blade, shaving foam, deodarant etc.)
3. A flexural eczema such as Flexural Serborrheic Dermatitis
I would suggest trying 1% Lotrimin cream - mix this in a 1:1 ratio with the Cortisone cream you have and apply twice a day on the affected areas. Orally take Tablet Claritin 10 mg once or twice a day depending on the severity of the itching or burning and try and stay as cool and dry as possible. Wear cotton clothes and undergarments as much as possible.
Give this regimen 3-5 days to work - if the rash looks like it is improving then continue the creams for 14 days or so and that should take care of the problem. If you sweat a lot in the area then additionally use Zeasorb-AF powder 5 minutes after the creams in the morning to help keep the area dry.
All of the above are available over the counter without a prescription.
If you don’t see any improvement in 3-5 days then it would be best to see a doctor in person.
Please feel free to ask if you have any queries. I will be happy to continue further and do everything I can to provide you with the service you seek.