Well my beer is just under temperature so I know it will take a bit longer to ferment but I added my lager hops. Do you think this may effect my lager in any way?
Thanks for clarification in the comments. The upshot is:
- fermentation temps externally are 16-17c, although instructions say 20-25c
- hop pellets were added at day 10 to the fermentor
Firstly, this isn't a true lager kit that you have. Lager is made with a different species of yeast compared to Ales, one that ferments typically in the 5-12°C range, while ales ferment in the 14-25°C range. From the temperature guidelines of 20-25°C I can tell you with confidence that what you have in the pack is an ale yeast, not a lager yeast. This is very common with so-called "lager" beer kits - they ship a regular ale yeast to try to make it easier for the brewer so they don't have to chill the beer. As a result, the beer is fruitier and lacks the crispness of a true lager.
However, by reducing the temperature as you did, you reduce the fruitiness of the beer and other possible off-flavors, so you did yourself a favour with the lower temps!
The lower temperature has no bearing on the hops you added, which are unaffected by a few degrees difference temperature. The hops added to the fermentor will give your beer a stronger hop aroma and flavor.
All in all, this beer will probably be better than if you followed the instructions exactly!
I am going to make an assumption that the word lager on your hop sachet meant in the sense of storing for a period of time, like the German word that "lager" is derived from. I refer to that as dry hopping. So, you think you've added your dry hops a little too early.
There probably wont be a huge problem with your beer. If your fermentation was almost done, you're better off. Two issues are infection risk and perhaps lessened hop aroma. Because hops are not sterile, adding them during rapid fermentation can increase risk of infection. Secondly, hop aroma can be released with the CO2 of heavy fermentation, making your final product seem less hoppy.
TL;DR: You're probably fine.
Further reading on dry hopping here