I injected tesosterone im last thursday and think I hit a vein, how long is the danger window? Or am I out of the woods?

No concern. There is no danger at this point, the concern with hitting the vein is that the medication can go directly into your blood.
1 Event On Record. I agree, you are out of the woods. There is only 1 serious adverse event on record. There is a case report that a gentleman suffered a cereral vascular accicent {stroke} after injecting too much testosterone. His level was 11, 400 ng/dl at that time. From my experience, one would have to inject the whole bottle in order to get a testosterone level that high.