When will NEM rise back upto 470 sat like we saw weeks ago?

It's coming...but for right now there is a campaign underway to drive the price down. The price scalping that is going on right now does not by any means reflect the value of NEM. It's impossible to determine the reason for this (disgruntled investors, another coin threatened by NEMs' progress, a whale looking to shake out weak holders and accumulate cheap coins, or just because BTC is on a little run), but one thing is certain...this will continue as long as the trading volume remains low because the spread can be easily controlled.
The bright side is that the power of the NEM platform cannot be denied. People and countries will eventually catch on and when that excitement and trading volume hits the market the valuation issue will go away. I, like you and many others, have been frustrated by this and can't understand why other crypto coins run so hard on weak platforms, theory, and controlled lab tests. We know what NEM is capable of in the "WILD" thanks to the efforts in Japan. This means so much more than the lab benchmarks and puts NEM that much closer to market dominance.
Hold strong...it will be worth the ride!
Some investors of NEM are diversifying their assets. New DAOs are getting a lot of attentions plus the ICOs being participated . But it is healthy for NEM environment. Potentially, NEM has the most reliable and strongest P2P platform for business.