Single sore Unser foreskin

hi so on the weekend i noticed a red single sore starting to appear under my foreskin. it got worse the next day but after leaving it alone and just bathing in warm water its seeming to get better, obviously iv been googling it but cant find anything exact.. im pretty sure its not herpes cz my parter is fine and its not a cluster of sores or blisters. any ideas

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I have something similar. Did you get a diagnosis?