Once the neoprene rubber is punctured it is best to use up within time frame of dose prescribed so as an example if it was 100mg/ml strength and the dose prescribed for trt was 100mg/week than it would last roughly 10 weeks if there was no wastage depending on syringe used and whether one is swapping needles for drawing/injecting.
There would be more waste when one is not using a low dead space syringe with a fixed needle (insulin syringes).
Hard to say if the potency has degraded slighlty as it has already been punctured and sitting around for just over 3 months.
The oily solution has thickened possibly due to stale air in the vial or if it was stored in a cool place.....as many inject air into the vial before drawing.
You could try warming the solution up to see if the viscosity improves and give it a shake.....not sure how much is left in the vial and if it is really worth it.