Yes there is a genuine risk using out of date medication. Risk means this is a possibility of harm. It doesn't not mean it is guaranteed, so you should not use anecdotal reports or "personal experience" from others to make you decision. You might only get replies from those where the risk did not materialise (yet....) There might be others where it did and they are no longer posting on these boards so your "survey" will be biased.
In the last 9 months I have been on these boards I have read of two individuals who used out of date pens and had horrific side effects, one hospitalised. Again, there is no "proof" it was the medication being out of date that caused it so it cannot be used as definitive that it is harmful.
It is not a simple black and white - will it harm me or not every time I do this. You are an individual, your response to out of date medication might be different to someone elses. Your pen is one instance, its condition from storage, use, etc will be different from someone elses pen.
Your decision on safety should in no part be based on the cost of the pen. Or on unprovable, and a bit tin hat, theories it is all a big commercial lie. It might be, but it also might not be.
Your decision should be based on your own research and willingness to take the risk and bear the possible consequences. Would you inject your child with significantly out of date medication? If not why not and why do it to yourself?
My own personal take. I take 6 doses from a pen stored in the fridge. The 6th dose is on day 35, 5 days over the discard date. I accept what I believe, from my own tolerance to risk and what I have read outside of social media, to be a low risk - up to others to risk assess for themselves.
7 weeks? You do you, but for me it would be a big no.