Hello from JustAnswer.
Could you attach a picture of the area?
Which creams have been used thus far?
It is possible that someone may have excessive genital dampness simply because of overactive sweat glands, but it would typically not cause a ring such as you describe. However, a common medical cause of dampness that also can cause a ring on the genital or groin area would be a fungal infection. It is more often a dermatophyte type of fungus, although a yeast infection can be the problem.
While the appearance can suggest whether it is a fungal infection, it would be a more definitive diagnosis to perform a microscopic examination of scrapings of the area.
If the timodine ha not helped, there are a couple options. It would be reasonable to try an antifungal cream in a different chemical class, such as clotrimazole. Another option would be the use of an oral antifungal, such as fluconazole, particularly if there is a failure to respond to various topical antifungal medicines.
If I can provide any additional information, please let me know.