You seem to be having multiple problems.
Looks like you have a fungal infection
of the groin. This upon itching can lead to development of boils which are actually infective lesions of the root of the hair follicle.
Next you developed oral aphthae.
Now all of these can occur secondary to intake of some oral antibiotics
I would advise you to use a topical antibiotic
cream over the boils .
Take oral multivitamins which will help in healing of oral lesions.
These symptoms do not seem to be associated with any Sexually transmitted disease
Hope it helps
Best wishes for a speedy recovery
Dr Geetika Paul