In chicken pox how long does the rashes come?

Incubation. The incubation period for development of chickenpox is 10 to 21 days after exposure (to chickenpox or shingles). The rash becomes blisters that itch. Blisters usually have all transformed into scabs in about a week. .
For about a week. The rashes are from the different stages it may last for 2 weeks. Sarts with a red spot and then blister and scab.