A rough, crinkled paint surface, which occurs when uncured paint forms a 'skin'.
Paint applied too thickly (more likely when using alkyd or oil-based paints)
Painting during extremely hot weather or cool damp weather, which causes the paint film to dry faster on top than on the bottom
Exposing uncured paint to high humidity levels
Applying top coat of paint to insufficiently cured primer
Painting over contaminated surface (e.g. dirt or wax)
Scrape or sand substrate to remove wrinkled coating. If using a primer, allow it to dry completely before applying top coat. Repaint (avoiding temperature/humidity extremes), applying an even coat of top quality interior paint.