bodom85,
Sorry to say but this is not a good situation. Yes chameleons are often injured in holding facilities by other chams because they are often crammed into cages with multiple species and way too many animals. The problem becomes that any injury is almost always infected because of the environment of the cages, the unsanitary conditions, the stress level of the animal suppressing the immune system, and the poor nutrition/hydration of the animals during transport and holding.
The veiny things you see are nematodes under the skin. This is a parasitic worm transmitted to the animals in the wild by biting insects. It is almost never found in CB animals. The only way to remove them is to have a vet remove them surgically and then go back several times for additional surgeries to ensure that they are all gone and any eggs that develop are removed. In the wild healthy chameleons do not seem adversely affected by them, but the stresses of captivity often result in the infestation of the chameleon. Do a search there are pictures of chameleons swarming with them under the skin; they will need to be removed.
In addition to these parasites the WC animal needs to be subjected to fecal floats/smears to detect the level of internal parasites it carries. There is no question of "if", only how many. You will need to run a cycle of Flagyl and Panacur then run fecal floats again. It may take several cycles to bring the internal parasites under control and eventually eliminate them. In addition you will need to treat the infections caused by the wound with Batryl, there is infection there, without doubt, and without treatment it will move into the bones of the skull and you will have no hope of saving the animal. The problem becomes that you generally need to treat for parasites before running antibiotics, you may need to run a shotgun approach however and just hope for the best because of the obvious injury.
There is a forum thread on saving chameleons and the dangers/ignorance of such attempts by novice keepers here.
Sleepy Chameleon
Senegal is not a good first cham by any stretch. You can find information specific to the species and its care and breeding here.
AdCham Senegal Chameleon Profile
Did you pay for this animal or did they give it to you? If you paid for it I would take it back and let them deal with it. If they have no return policy then I would do no more business with them as they obviously do not care about you or the animals they sell.