Hi.You might have acquired Genital Herpes
infection.It is a viral disease,occurs when there is low immunity like fever ,but subsides on its own.No need for specific treatment.If it is hurtung,you can take Oral antiviral
drug which is active against Genital herpes.Regarding itching over the scrotum,it may be due to fungal infection
.keep it clean and dry.Consult a dermatologist
if the symptoms persist.take care.