Skimming over bonding

#1
Hi I’m new on this site and need advise. I have bonded a full bedroom a week ago. A couple of days ago I skimmed each wall with 2 coats of multi finish all the walls were smooth and perfect when I finished. My other plastering friend said it was perfect. When back today all walls are still wet and have loads of bumps on the walls. The house is empty. The walls were perfect when I finished the skim. What could be the problem please help thankyou