Nasty rash under dd's arm

[trickynicky]

I think she's tried to shave under her armpits (she's hardly any hair at 14 years old!)....but she has a hideous rash which goes all the way down towards her tummy from her armpit. Could it be a reaction to deodorant perhaps? She doesn't want to go to the docs. Any idea what creams I could buy which might help? She used a bit of hydrocortisone cream that I had on it and it seems a little better but still bad.... any experience anyone?
Thanks

Go to the docs - my mate had this. Did it appear all of a sudden? It could be a skin infection caused by a blunt razor damaging the top layer of skin and leaving it broken and open to infection. If it is the same anti bs cleared it up quickly

is it just from one armpit? Has she had chicken pox before? It could be a shingles rash