Could this be some type of skin cancer?

I used to go tanning quite often.. but now I limit myself about 1-3 times per week. I do have a lot of little "beauty marks" on my upper arms. They are very small and brown, but I don't call them moles simply because they don't raise above the skin, lol.

A couple weeks ago I noticed that either a few I did have and didn't know I did ..started changing color, or they were never there and they just popped up.

Both sound silly, but what bothers me is they aren't completely brown. I have like 4 that are very small ..brown, but it seems like the edges of them are pink-ish.
Do I have the need to worry?

[I'd link a picture but everytime I take one, you can't see anything.]

Once or twice a week really isn't that often. I understand that UV rays are harmful, but isn't it about the same if you were to go to the beach friday & saturdays?

Tanning is sooooo bad for you. Yes, it is the same as going the beach, unprotected without sunscreen twice a week, which is also soooooo bad for you. Do you understand what a tan is? You have these little cells in your skin called melanocytes. they produce the pigment melanin, which gives your skin it's color. Darker skinned people have more melanocytes. A tan is the result of melanocytes bursting and releasing their pigment as they die. Pretty gross, huh... A tan is actually the 'guts' of your dead cells... So, quit tanning, wear sunscreen, I promise, you will look better with your natural skin color and be much healthier! And don't forget... tanning causes wrinkles. I have friends in their mid-twenties who look like they are in their early forties because of tanning.
About the moles....the guidelines that health professionals follow are the ABCD rules
A is for asymmetry. Moles that are not the same on both sides should be checked out.
B is for border. Border should be regular and smooth. if it is jagged, go get it checked
C is for color. moles should be uniform in color, which varies from light to dark brown. Black, pink or red moles, or moles with uneven color should be checked.
D is for diameter. The mole should be no larger than a pencil eraser.
These rules do not apply if you have had the mole your entire life and it hasn't changed. If your moles have exhibited any of the following changes, or you have developed any new moles, you should be seeing the dermatologist.

You need to see a dermatologist. You have been tanning entirely too often. Tanning beds are NOT a safeguard against skin cancer, in fact, they have been shown to INCREASE the incidence. Just because a mole is not raised above the skin doesn't mean it's not a mole. And the pink edges are a red flag. Get to a Dr. and stop tanning.
Alot of people comment on how pale white I am, but I like that alternative better than skin cancer.

Edit: Ask a dermatologist if once or twice a week is too much. See what answer you get. You are causing irreparable damage to your skin, and not just the epidermis. You're also causing damage to the dermal layers too, causing premature aging. I don't know how old you are, but if you don't want to look like a prune at 45, I would take care of your skin. No amount of plastic surgery can undo the damage you are causing right now. And once you GET skin cancer, the incidence of getting more and more goes up exponentially.