Hi there Michaella.
It does appear from your history & clinical description that you ail from a condition called 'intertrigo'.
Now, this can be either a
fungal infection or a bacterial or admixed.
If the cream the doc gave you helped clear it the last time, by all means use it again for a further 5 days to a week & then shift to a 2%
ketoconazole cream applied locally twice/day for a further week.
In addition if you can manage to go across to a doc/GP, please take a one time dosage of a
Fluconazole 200mg capsule/tablet as a single dose; If possible, combine it with a single dose of 2Gm tinnidazole at the same sitting. This does come in a 'kit' or combination dosage in some countries.
Take care & am glad you are devoid of all STD's; However, do practice
safe sex & good hygeine..by that i mean wash all your undergarments/towels/fomites in hot water & dry well in the sun as these fungal infections tend to recur; keep your clothes'/cupboards' well aired & do not wear damp undergarments to prevent recurrences!
Good Luck & wish you great health!
Dr Praveen Rodrigues MD
Dermatologist, Cosmetologist, Venereologist
Vikram Hospital, Bangalore, India