Thank you for the photographs. This could just be a healing penile abrasion (as can occur during rough sex or masturbation) and for now I would suggest you apply a moisturizer on the area twice a day - something like Cetaphil Restoraderm or Aveeno is great. Give this a week - if the patch clears up well and good. If not then other possibilities need to be considered and the two main ones are Penile Psoriasis and Seborrheic Dermatitis
Seborrheic Dermatitis is a type of dry eczema
and Psoriasis is an autoimmune condition of the skin where it is made faster than normal in certain areas. Both tend to get scaly when fully developed but in the early stages may just be a faint red patch like you have.
Both conditions are best treated with prescription creams like Mometasone or Fluticasone (combined with Eberconazole in the case of Seb Derm). However if you cannot see a doctor for any reason then here is an over the counter regimen that can help:
1% Cortizone cream + 1% Clotrimazole cream: Mix in equal parts and apply twice a day for 14 days over the affected area. If it looks better then continue applying them once at night for about 10 days and alternate night for 10 days more and then stop.
NOTE: All of the above are available without a prescription.
Neither Seb Derm nor Psoriasis are sexually transmitted so don’t worry on that account. However avoid sex and masturbation for a few weeks if possible to give the penile skin a chance to recover.
Pleased feel free to ask if you have any queries. I will be happy to continue further and do everything I can to provide you with the service you seek.