How can increase the resin at this time, and make ...

Typically at this point in bloom decrease the nitrogen, increase the phosphorus (increases bud sites) and potassium (increases density). Some thing like PK 13/14 works well. Giving the buds plenty of light (intensity) with an increase in the red spectrum will also help with bud density. Also keeping temperatures around 75-76 in the last few weeks of bloom with lower humidity 35-40% is best to preserve terpenes and THC. There are also some products which claim to enhance resin and terpenes but you will get a variety of opinions that they really make a difference. Good genetics = Great bud. Indica strains tend to have denser buds than sativa. Skunk has both. Hope this helps