Thank you for writing to JustAnswer Health with your question.
From your description it does sound likely that this is a fungal infection. The only sure way to know is examination. The most common is types of fungal infection to this area isTinea Cruris which is commonly called 'jock itch".
The creams that work well for this, which do include Lamisil, but also, clotMiconazole, and butenofine are creams that are usually applied from 1 week to 4 weeks. Some of the creams to treat this are available over the counter, but stronger creams and oral medications that may work better with resistant infections require precautions or lab's first (to check for liver function, for example) and may also require a prescription. An oral anti-fungal medication such as fluconazole is prescribed in some cases.
As it sounds like you are aware of, it is important to keep the area clean with mild soap and water twice daily, drying very thoroughly afterwords (actually, do not use an antibacterial soap, because this can kill the normal bacteria that is present on skin which helps to keep over-growth of fungus from developing). Wearing cotton underwear and loose enough clothing so that air can get to the area to keep it as dry as possible, is also important because moisture is a factor in that helps keep the infection growing and continuing.
It is also important to use good hand washing to prevent spread to other areas such as the eye, although this is less likely to happen in a person with good immunity.
In 1/2 of men with topical fungal infections such as genital Tinea Cruris it has originated from the feet to the genitals, so it is important to be aware of this if you have any type of infection or itching on your feet as well, to treat the feet as well, and to be careful when putting underwear over feet to prevent recurrence. Also protect your feet if you use a public gym with flip flops or thongs.
The anti-fungal creams miconazole or clotrimazole are also effective against yeast infections (Candida albicans) another type of fungal growth, but your infection sounds less likely to be a yeast infection.
Since you have already tried two types of creams, it is recommended that you see a physician for the next step, which is collection of a small biopsy of the lesion or affected area for microscopic (laboratory) examination. This will allow for determination of the exact organism so that the exact treatment you need can be started.
Any physician commonly treats these infections of the genital region and does not think another thing about examining a person in this area -- you need to look at doctors as being similar to a mechanic, they check individuals "under the hood" every day, so there is really no need for you to be hesitant to be evaluated for any kind of infection that is possible in this area.
If you have questions or comments please reply to this post so that I can assist you further.