I have reddish blotches under my skin on my arms?

ok so here it is i have like reddish blotches under my skin on my arms...its not itchy and has no pain to it but is very weird...there are acouple of spots where its alittle raised like 2 bumps in about 3-4 spots but not all over..my arms contantly hurt in my muscles and joints but not to the point where i cant do anything just very annoying,..ive had this for about a week and a half now and i dont know what it is...i set up an appointment with a dermetologist and the appointment is not for a week so i wanna see if i can find something in the mean time..its only on my arms though too which is weird no where else on my body..is this something i should be worried about or is it because its hot out and ive been working in the yard the past couple of days..ive worked in the heat before though and none of this has happened..im a 29 year old male with no medical problems or any STD's ever...Please anything would help..thanks for your time in advance