If a 14 year old boy has chest hair and facial hair that you can see a little bit the day after shaving can he grow 3 more inches?

Yes: 14 years old boy is in growth spurt period and will grow 3inches more .they keep on growing till 18-19 ears of age .

Growth: this is not really related. Depending on several factors, genetics being the biggest determinant, growth can continue into the mid-teen years for males. A little bit of chest or facial hair won't determine if there is more growth potential. Talk with your pediatrician who can review your growth chart with you.