Hi, I have never used lustra, but from what I have heard it should work fast( because of the 4% concentration ), and also since you are using this in conjunction with glycolic acid.By the end of two months or so, your blemishes must all be faded completely, pretty much. Don't also forget to use sunscreen regularly.
Recent studies indicate that hydroquinone is a potential carcinogen. Its use is banned in several Asian, European and African countries, although it still continues to be used in the US. Also your's is a higher concentration, so make sure to not use it for too long. Do try to read about this.
I have just started using a hq-based product, which is only 2%. It seems to be working well, but I will quit using it after 2-3 months no matter what.