My moms veins on one foot are swollen and hurting. What's going on?

Needs exam. This situation needs an examination because it can be due to several things including varicose veins.
More info is needed. To receive an answer that will be more helpful, you need to give more information...Your health status, any problems such as gout, diabetes or blood pressure concerns. You should state how long it has been a problem and what you do to make it feel better. Also tells us what it looks like. Is it discolored, swollen or point tender. The more you tell the better the answer.