Hi there!
An external examination is very important for confirming any diagnosis. Based on the information shared by you there are a few possibilities. These white dots could possibly be pearly penile papules. Pearly penile papules are small white colored dome shaped forming a row around the head of penis or on either side of the frenulum.They are usually harmless and begin to appear around the age group 20-40 years. Regarding the line between testicle sac having white dots it can be due to friction, allergy or any infection. A clinical examination is very important for accurate diagnosis. Do see a dermatologist. I do hope it helps.
Take care and regards!