I Am 21 Years Old Male. I Have Red Rashes

I am 21 years old male. I have red rashes on my lower neck area, arms and lower portions of legs. They itch a lot and haven't reduced for the past 2 days. This is probably due to bed bug bites since I moved to a new place a week ago and there were bed bugs and it wasn't until a few days after moving that I could spray insecticide. I don't have any other symptoms. I firstly wanted to confirm whether this is only a bed bug rash or not. If it is what should I apply or what else treatment would be imperative. Also, after how long should I expect these red marks(rashes) to go away. Also, are there any other precautions or advice that I should follow regarding the same.