Guttate psoriasis
Guttate psoriasis is a type of psoriasis that presents as small (0.5–1.5 cm in diameter) lesions over the upper trunk and proximal extremities; it is found frequently in young adults. The term "guttate" is used to describe the drop-like appearance of skin lesions. Guttate psoriasis is classically triggered by a bacterial infection, usually an upper respiratory tract infection.:

The number of lesions can range from 5 to over 100. Generally the parts of the body most affected are seen on the arms, legs, back and torso.

The treatments used for psoriasis can also be used for guttate psoriasis. The condition often clears up on its own within weeks to months, and only about one third of patients will develop chronic psoriasis.

Treatment ― OTC Drugs
It often disappears spontaneously over time. It may take about 1 month.
#OTC steroid ointment

  • Lesions on the back torso. A large number of small, scaly macules or patches occur on the trunk after symptoms of a common cold. Because it improves when exposed to sunlight, it mainly occurs on the trunk
    References Guttate Psoriasis 29494104 
    Guttate psoriasis is a distinct variant of psoriasis that is classically triggered by streptococcal infection (pharyngitis or perianal) and is more common in children and adolescents than adults. Patients present with several, small “drop-like” lesions that respond well to topical and phototherapies.
     Childhood guttate psoriasis: an updated review 37908643 
    Guttate psoriasis is common and affects 0.5–2% of individuals in the paediatric age group. Guttate psoriasis typically presents with an abrupt onset of numerous, small, scattered, tear-drop-shaped, scaly, erythematous, pruritic papules and plaques. Sites of predilection include the trunk and proximal extremities. There may be a history of preceding streptococcal infection. Koebner phenomenon is characteristic. Guttate psoriasis may spontaneously remit within 3–4 months with no residual scarring, may intermittently recur and, in 40–50% of cases, may persist and progress to chronic plaque psoriasis. Given the possibility for spontaneous remission within several months, active treatment may not be necessary except for cosmetic purposes or because of pruritus. On the other hand, given the high rates of persistence of guttate psoriasis and progression to chronic plaque psoriasis, some authors suggest active treatment of this condition.