sounds like camellia/azalea leaf gall which can affect leaves and buds. if it is that, the disease is caused by a fungus.
hand picking and disposing of the infected parts is the recommended practice. it can also be controlled with fungicide.

I agree 100%.

Enlarged, crabapple-like, green or pinkish galls on young leaves and flowers are caused by Exobasidium Leaf and Flower Gall. The galls become hard and turn white and eventually brown. While very noticeable, these galls will not threaten the health of the plant. This problem is more common during cool and wet spring weather. The first symptoms are swollen or puffy portions on newly expanding leaves, shoots, buds or flowers. The galls range in color from green, to pink or red depending on the part of the plant infected. As these galls age they develop a white surface growth which is a layer of reproductive spores. Eventually the infected tissue will turn brown and shrivel up into hard galls. Fungicides seldom provide control. Sanitation (removal of diseased parts of the plant) and warm dry conditions reduce infestation. It is seldom considered serious. It is most common of evergreen azaleas.

Exobasidium Leaf and Flower Gall, Exobasidium vaccinii, is a very common fungal disease in the spring during wet, humid, cooler weather on azaleas and occasionally on rhododendrons. Some of the native rhododendron species (azaleas) are more susceptible than hybrid rhododendrons. In April and May leaves and buds of infected plants develop distorted growth. The fungus invades expanding leaf and flower buds causing these tissues to swell and become fleshy, bladder-like galls. Initially, the galls are pale green to pinkish. Eventually, they become covered with a whitish mold-like growth. Fungal spores are produced within the white growth and are spread by water-splashing or wind to other expanding leaf or flower buds, or they adhere to newly formed buds, over-winter, and infect these buds the following spring. Older leaves and flowers are immune to infection. As the galls age, they turn brown and hard. The disease does not cause significant damage to affected plants. It just looks unsightly. If only a few plants are affected, pick and destroy galls.

Here is a link that might be useful: How to grow azaleas and their problems.