The rashes you have are a result of the shaving and are commonly known as razor bumps. They also resemble a rash because they can look like a bad breakout of acne on the skin.
It basically happens in areas where the hair is curly and has a tendency to pull backwards into the skin. What happens when you shave is that the hair gets cut fine at an angle and starts to curl back into the skin. This causes the hair to pierce the skin and thus the body reacts as if it's fighting an infection and causes a painful swelling which leads to the formation of the characteristic red bumps. This is a normal defense mechanism of the body and is a normal occurrence. The inflammation is basically caused due the nerve endings being stimulated. And the nerves reaction to stimulation is inflammation.
There are various ways in which you can remedy this. All you have to do keep in mind certain tips before shaving and while shaving and you should be able to avoid having a break out of rashes in the future. The first thing you can do is to soften your hair using warm water. The warm water helps moisturize and thus softens the skin. This will make it easier for the razor to remove the hair and avoid the amount of hair that gets pulled out by the razor instead of getting shaved off. You can do either one of the two things. You can either shave after you have taken a shower or you can use a towel soaked on water to moisturize the area. The other point to note is that when you shave, never try and shave against the direction in which your hair is growing. Also always remember to shave the same area more than twice or three times.
answered by M W