3.75mg is 45 clicks in a 5mg pen. You will get 5 doses, always do each with a new pen needle, without having to use a syringe or hard twist.
There would, in theory, be enough for a 6th dose, you would get around 23 clicks without breaking the pen, then you would need to hard twist to get to 45 again (or use a syringe). Doses would be on days 0,7,14,21,28,35. Meaning 6th dose would be 5 days over the discard after 30 days instructions. Eli Lilly have remained consistent saying pen should be discarded after 30 days. It is up to you and your attitude to risk if you wish to use medication you inject beyond it's discard after date not knowing why it should be discarded - it may be ok, or it might be unstable/contaminated or just simply not as effective. Cloudy indicates a problem with the medication, clear does not mean it is safe.
If you are using 45 clicks it helps to mark the 45 click point in the window with a ball point pen the first time you do it to know where you are going to each time if you lose count!
I have read some providers, not all, challenge patients who are regularly not ordering pens on a 4 week schedule as adjusting doses is off license to what they should prescribe to.
Discarded medication is not "wasted" if you get 5 doses (already 1 more than you should have) and have the effect you wanted for those 5 weeks.