There is a possibility that it is peri-herpetic keratosis.
Keratosis pilaris is a chronic keratotic skin disease of the hair follicle, often occurring on the arms and anterior thighs, symmetrically distributed. The affected area has a peculiar roughness of the skin, with pinpoint to corn-sized papules at the pores, which are the same color as the skin and have light brown keratinous plugs at the tip containing curly hairs. Small funnel-shaped depressions are left after the keratin plugs are peeled away, but new keratin plugs will soon appear again.
The disease often has no specific symptoms, is sometimes slightly itchy, and is heavy in winter and light in summer.
If a definitive diagnosis is desired, prompt medical attention is recommended.