After an ultramarathon, you’d expect your legs to be in rough shape. This was true for Julie Nisbet, a first-time ultrarunner, according to her Twitter. But not in the way you’d expect. 

After completing The Wall, a 69-mile challenge between Carlisle and Newcastle in the U.K., she was left with a severe sunburn that caused large blisters to bubble under her skin, The Sun reports. 

Julie Nisbet‏ Horrific Sunburn
Twitter/ Julie Nisbet‏

Nisbet ran for more than 21 hours (just 8 seconds shy of a sub 21-hour 110K run, she posted on Twitter).

Here is one of the least graphic images of her legs.

She’s been posting updates of the healing process on Twitter. The puss-filled blisters have been drained and dressed on multiple occasions, though it seems as if she’s on the mend.

You can understand how she overlooked or forgot to reapply sunscreen—what with the excitement and nervousness of running such a tremendous race paired with the physical challenge of traversing 69 miles, hydrating, eating, and making pit stops for bathroom breaks—but it doesn’t undermine the lesson. Sunscreen is absolutely key for athletes training or competing outdoors for an extended amount of time. If anything, her tragic experience stresses the importance of sun safety.