H4 stamp expired. H4 petition approved. Going for F1 stamping. What in case of F1 rej

[Mastersinus]

I am on H4 visa. My H4 petition is approved till 2018 , however H4 stamp on passport is expired. I am planning to go for F1 stamping in India. In case of an F1 rejection, how soon can I go for H4 stamping? Will it risk my H4 stamping?

Is it possible to go for H4 stamping first and then within a months time go for F1 stamping again? Will this risk my F1 stamping?