Hi there =)
Sorry to hear about you boy. Those lumps are actually fairly normal but perhaps your boy is a little underweight if they are showing up so much. However, his behaviour is worrying. Bettas are by their nature curious, fairly active little fish. They like to watch what is going on around them and follow movement. They tend to be very greedy and love food. While they do like to rest and sleep, they shouldn't be hiding away a lot of the time.
I am sorry to say, but he does need a better environment. Bettas often get sick or behave strangely when the environment they are in is not ideal. This is because toxic water (from no filter and/or too few water changes) and low temperatures take a toll on their bodies, making them stressed and sick. They also need plants to play in and places to hide. These make them more secure and improve their behaviour.
Bettas should have enough space to give them different places to explore. While upgrading from a bowl is not the most immediate problem, you really should consider it. Bowls are difficult to heat and filter and they generally do not provide enough space for the bettas to stay fit and healthy. Bettas can actually die from a condition called "fatty liver" if they do not get enough exercise.
Bettas also need warm temperatures of arounf 25-27 celcius (77-81F) that stay stable. In a unheated bowl, the temperature would swing by several degrees during the day and night. which is stressful for the fish and bad for it's health. They, like all fish, also need filtration to naturally keep the toxins in the water down (using special bacteria that can be grown to live in the filter) or they will need daily water changes if kept in a bowl as the waste they produce (jn their poo and wee) is very dangerous for them.
Unless you change these things, your better doesn't have much chance of getting properly well and behaving naturally.
There is a lot of great information
here on how to set-up, cycle and maintain a tank.