Once you’ve had one keratoacanthoma, you may be more likely to get others in the future. Check your skin regularly for any lumps or unusual spots, and see your doctor for a full-body exam twice a year. It’s also important to protect your skin from sun damage. Avoid going outside from 10 a.m. to 4 p.m., when the sun is strongest. Use a broad-spectrum sunscreen with SPF of 15 or higher. Wear sun-protective clothing and hats when you’re outside. Don’t use tanning beds.