Welcome
Yes it seems to be fungus.
Wear cotton clothes and undergarments(loose not tight) in order to reduce the sweating .
Take bath twice a day.
Avoid hot & humid.
Keep clean & dry.
Do not apply any kind of oils / moisturizing lotion over the affected area .
You should also avoid applying savlon over the affected area as it can irritate the area more.
Just give warm saline compresses over the affected area twice a day and then apply 
clotrimazole /miconazole cream  available at counter.
Also , you will need to take oral anti fungals in the form of 
fluconazole 150 mg once weekly for 2 weeks.
In case of 
severe itching, take  antihistamine like loratadine (loridin)  once a day in morning & 
diphenhydramine (benadryl) in ivening.
If inspite of the above measures, the lesions continue to persist or increase , then you might have to see a 
dermatologist for proper assessment and management .
Hope it helps, 
Take care.