It depends, everyone is different.. It helps to use ethyl alcohol, or peroxide, IME.. they seem to heal a bit quicker.. That is the thing I hate the most about being on the needle, is I constantly have to try and "hide" my so fucking obvious (sometimes at least!) track marks... especially when at work, being required to wear short sleeve t-shirts at my job, and constantly having to use my arms to pick things up, and well.. work.. lol. I have had my managers/bosses eyeball me hard before, like I have caught them staring right at the marks on my arms.. one guy asked me what happened, luckily not my manager.. I just said, I fell in a thorn bush and have had scars there forever.. I truly do have a couple track marks, from using the same veins to many times in the past, when I just started to shoot, that are still here, years later, and haven't gone away! it sucks.
IMO the ones on your arm, aren't bad at all, they aren't really even true "track" marks, they are just small red dots where you shot, not lined up or anything, hence the name "track mark" where numerous red dots like the ones on your arm form a scar like line, which people call track marks, those are just tiny needle marks on your arm, which you could easily blame on tons of things, besides shooting up!
The ones I have/had, were WAY worse than that.. like literally, 15-25 red dots, in a perfect line, running along my vein, right where my veins are totally visible all the time, looking like a scar.. I get very nervous, because some times, when I shoot coke, and get vasoconstriction, when the veins like to hide, and sort of "tighten" and become more thin, it becomes much harder to find them... and I shoot subutex daily too, so whenever I shoot coke, I also shoot subs that day as well... and well, it can become a royal bitch to hit a vein successfully and quickly.. so I have to keep hitting, the same vein, if its the only one I can find, over and over, and over.... it sucks.. but that's part of being an IV user.. just one thing that sucks ass about being an IVDU. Quit if you still can, and its not too late... not a good road to go down, wish I never did!
You can use make-up to cover them, if you have access to any.. that works.. or Neosporin, sometimes, works.. not always as quick as you might want, but it does work most of the time... I mainly only use it, when I cut myself, not for IV marks, as ethyl alcohol usually works just fine for me at least.. I also use peroxide.. and if I have neither of those 2 things, I use plain old hot-warm soapy water, which doesn't help much, but it does help..