I am caregiver of 5 years old boy he has fifth dissease and his cheek have red rash. i never have fifth dissease in my life, can i get contagious?

Not likely but maybe: 5th's disease is caused by human parvo virus b19 and more common in kids. Most adults are already immune from childhood exposure. It usually takes 4-21 days after exposure to become sick. The infected patient is most contagious right before the rash appears. So symptomatic patients do not require quarantine. You may not recall having the illness but were most likely exposed as a child.