Hypochondriac, freckles on arms, sun spots on knee

Hello, I recently have been getting some freckles on my arm and since I m a hypochondriac, I ve been freaking out over them. I m 13 and no cancer runs in my family. My mom has freckles all up and down her arms and I usually inherit all the stuff my mom has. My mom said that it happens when you get older in age. I think it was last week, I found my moms tanning lotion that she lets me and my sister use and so I put some on my arms and legs then I set in front of my window and I think ever since then, I found new freckles. Do you think I should worry? I also found a sun spot next to my knee . All my family and friends so I shouldn t worry and that their just freckles and sun spots and that s all it is. Also, do you know of any way that I can over come being a hypochondriac? I have been for about 2 years now and it always keeps me back from doing stuff. My mom already told me that the only type of cancer that runs through my family is Lung cancer and the only people that got it was the ones who smoked . So pleasssseeee tell me this is not a big deal... I m really stressing over it :/