There are several potential causes of this numbness
in your thigh.
First I would wonder if you were injecting any of your Lovenox shots into the area where you are numb. Although unlikely, it is possible that you could have damage a small nerve branch there with the injections or that the symptoms could otherwise be related to the local injection of the medication.
Second, I would be concerned to know that your blood is sufficiently thinned by the warfarin, and I would wonder what your last INR value is. For example, if your INR value is not high enough it could be possible that you are developing clots in your left leg. The resulting swelling could theoretically cause a number of strange sensations, including numbness.
Finally, I would wonder if you might have pulled or strained something in the groin, potentially totally unrelated to your recent hospitalization.
I would suggest that you call your primary care doctor
to set up an appointment. They will be able to perform a good physical examination and determine whether there is any chance that something serious is going on or whether additional workup might be needed.