If you pull down on your skin before you pin it will cover the hole when you pull out.

Are your delts still a lil sore like theres still a knot there when you go to pin it? I notitced that if I was to pin a area that was still knoted up and tight the oil would come back out more which makes sence because you pushing oil into a muscle that is still knoted and pressurized then there less room for the oil to go but out where it came from (the injection site). You could also try a 25g pin.

try the "Z" method... youtube it... might be difficult in your delts but not impossible.

I have the same problem sometimes. It will happen from time to time no matter what but to cut it down, I leave the pin in for a full min or so after the injection to let the oil disperse away from the site and pull the pin out in one quick swoop, the quicker the better and make sure the oil is warmed up so that its thinned up. The oil thickens when its cold and will be much harder for it to disperse from the injection site. Thats what I do and it seems to help a bunch.